Today in New York Weather History: October 25

 

1980

1.76" of rain fell today, with 1.15" of it falling between 10AM-1PM.

1991

Today's high temperature and those of the past two days: 72°-71°-70° (today) - well above the average high of 61°.

2005

In less than three weeks (Oct. 8-25) nearly 17 inches of rain fell, making this the wettest October on record (and, at the time, the second rainiest month overall; it's since dropped to third).  During these two-and-a-half weeks of deluges, seven days received an inch or more of rain.  In stark contrast, September had just 0.48" of rain, making it the driest September since 1963.

 

 

2007

Today's high was 57°, the first day this autumn with a high temperature below 60° - the latest date for this occurrence in the 1970-2021 period (average date is Oct. 7).  This balanced the 8/21 high of 59°, which was just the second time a high cooler than 60° occurred in the month of August.

2008

Mostly light rain fell between 4-9 PM, but then 0.62" fell in the hour between 9-10 PM.

2011

This was the third day in a row with a morning low of 50°.  Although the high temperatures on these days weren't identical, they were somewhat similar: 59°, 61° and 62°.

 

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September 2021 Weather Recap: A Record-Setting 3rd Month in a Row with 10+ Inches of Rain

 

 

September 2021 will long be remembered for the torrential rain that fell the night of 9/1, submerging streets, highways, subway tunnels and residences.  Nearly 50 deaths in the metro area were attributed to the storm (13 of them were in NYC).  This unprecedented deluge was produced by the remnants of hurricane Ida pushing up against a mass of cool air.  Between 5 PM and 1 AM, a little more than seven inches of rain poured down (with three inches falling between 9-10 PM). 

 

Although heavy rain had been predicted, its intensity in such a brief period of time took residents by surprise.  (And although hurricane Henri, two weeks earlier, produced an inch more of rain than Ida, it fell over the course of 48 hours). 

 

Never before had a month started with so much rain, easily breaking the previous record amount on the first day of a month, 4.98" on Oct. 1, 1913.  The 7.13" measured on 9/1 was the fifth greatest amount to fall on a calendar date.  (Earlier this year, February began with a record amount of snow for the first day of any month, 14.8".)

 

 

The rest of the month had slightly below average rainfall, but just enough to bring September's total to 10.03".  This was the most rain to fall in September since 2004, and it became the sixth rainiest September on record.  It followed the fourth wettest August (10.32"), and third wettest July (11.09").  Never before had Central Park had three months in a row in which each month had more than ten inches of rain. 

 

More than 90% of the month’s of rain was produced by two storms:  7.23” on 9/1-2 and 2.03” on 9/23-24.  0.77” fell on the other 26 days.

 

Looking at temperatures, September was 1.1 degrees milder than average, and was the 26th mildest September (tied with four other years).  However, it ranked 13th for mildest average low, and 55th for warmest high.  12 days in a row (Sept. 12-23) had above average temperatures, a streak of days that was four degrees above average.  The rest of the month was one degree cooler than average.

 

The warmest reading was 85° (on 9/15), the same warmest reading as last September (but it had two days with that high).  Also, both Septembers had seven days with highs in the 80s (the average is eleven).

 

Half of the days had highs between 75°-79°, which was double the average number - and the most to be in this narrow temperature range on record (second most is 13 days in Sept. 1999, 1927 and 1908).  Just five days had lows cooler than 60°, eight fewer than average.  Only Sept. 1971, 1930, 1908, and 1881 had fewer days (all had four). 

 

Finally, the month was also characterized by a narrow range in its temperature extremes.  Typically, September's chilliest reading is around 50°, the hottest around 90°, but this September it ranged from 54° (on 9/29) to 85° (on 9/15).  Only two other Septembers have had a range that was smaller.  (The greatest range in temperatures in September was 55 degrees in 1929, ranging from 44° to 99°.) 

 

 

Here are previous September recaps:

2020

2019

2018

2017

2016

2015

2014

 

 

 

August 2021 Weather Recap: Henri Rescues August From "Dullsville"

 

 

 

August was the fourth wettest August on record, but until 8/21 the month had been a dry one, with rainfall 50% below average.  Then, Hurricane Henri produced 8.19" of rain over three days (Aug. 21-23), accounting for nearly 80% of August's 10.32" of rain.  (The other 28 days of the month had just 2.13".)  This was the second month in a row with more than ten inches of rain (July had 11.09", making it the third wettest July),  just the second time this has happened (however, the first time, in March and April 1983, is disputed since the rain gauge in Central Park wasn't functioning properly for much of the year).  Although August's rainfall was less than an inch below that of July, its number of days of measurable precipitation was half as many (nine vs. eighteen).

 

 

One out of four Augusts have been warmer than July, and August 2021 was one of them (77.5° vs. 76.0°).  The month was 1.4 degrees above average, making it the City's 17th hottest August (out of 153).  However, there was a disparity in rankings of the average high and low, as only five other Augusts have had a warmer average low than this August (2.2 degrees warmer than average), but the average high (just 0.6 above average) was ranked much lower, at #39.  This difference in rankings wasn't unique to this August, as the trend during the 2000s has been for overnight temperatures to be more above average than daytime readings (one of the effects of global warming).

 

After the first five days of the month were five degrees below average, the rest of the month was three above average (with only five of the 26 days having cooler than average mean temperatures).  August had five readings in the 90s, one more than July, and it had five more days than July with lows of 75° or warmer.  August's days in the 90s were comprised of back-to-back days on Aug. 12-13, and a three-day heat wave two days after Henri's departure (Aug. 25-27).  The month's hottest reading was 94° on 8/13.

 

Finally, this was the eighth year in a row in which August had no readings in the 50s.  The coolest temperature was 63° on 8/2.  (Meanwhile, July's streak of 12 years with no lows cooler than 60° was broken this year). 

Here are monthly recaps for past Augusts:

2020

2019

2018

2017

2016

2015

 

 

 

 

 

 

   

July 2021 - Third Rainiest July Keeps Mid-Summer Heat in Check

 

With 11.09" of rain measured in Central Park, July 2021 became the third rainiest July on record (behind 1889 and 1975), and 15th wettest month overall.  This was New York's first month with ten inches or more of precipitation since June 2013 (10.10"), and the most to fall in any month since August 2011, when 18.95" flooded the City (the greatest monthly amount on record). 

 

A little more than half of July's rain fell on three days between July 8-12: 2.27" on 7/8; 2.06" on 7/9, and 1.42" on 7/12.  The amounts of 7/8 and 7/9 set records for the dates.  8.49" of rain fell in the first 12 days of the month (and 9.14" if 6/30 is included), then 2.60" fell thereafter (which was slightly below average for that period). 

 

There were 18 days of measurable rain, which was the second greatest number of days with rain in July.  July 1871 had twenty days, but just half the amount of rain as July 2021.   (Of the 27 months with ten inches or more or precipitation, the average number of days of measurable precipitation is 13.) 

 

Besides being rainy, this was the coolest July since 2009 (and 0.1 degree cooler than July 2014).  When all Julys are considered, July 2021 is in the middle of the pack, temperature-wise, with 54% being warmer.  The combination of a warmer than average June (+2.3 degrees), and July being 1.5 degrees cooler than average, placed these two months closer together (1.7 degrees) than any June/July combo since the summer of 2001 (when July was just 0.3 degree warmer).  Looking at average high and low, July's average high of 83.0 was just 0.5 degree warmer than June's, while the low of 69.0 was 3.0 degrees milder.  Because many days had dew points in the 68°-73° range, the air often felt oppressive rather than cool.

 

 

For the first time since 2009, a reading in the 50s occurred in July - 59° on 7/3.  And on 7/3, the high was only 66°, which was the first high cooler than 70°in July since 2013, and the coolest reading in July since 2005 . The month's coolest and hottest readings were three days apart as a high of 92° occurred on 7/6 (and the 59° reading came three days after June's hottest temperature, 98°, on 6/30).

 

July had four days in the 90s, half as many as June, and the fewest such days in July since 2014, which had three.  (Seven of the Julys between 2000-2009 also had four or fewer days in the 90s.)  Although the number of days of 90+ was half the average for July, the number of lows in the 70s, 16, was an average am0unt (but ten fewer than last year's record amount).

 

July had 8.47" more rain than June's 2.62", but there have been ten other instances where the disparity between two months was even greater (looking only at wet months preceded by dry ones).  The greatest difference occurred in  Sept-Oct 2005, when October had 16.73", which was 16.25" more than September's bone-dry 0.48".

 

Finally, after suffering through sweltering heat, and a nighttime thunderstorm on the last day of June, the last day of July couldn't have been more different, as skies were clear and temperatures on the cool side (high/low of 77°/60°).  While 6/30's high of 98° (14 degrees above average) was the hottest reading on that date since 1964, 7/31's low of 60° (ten degrees below average) was the chilliest since 1956.

 

 

Here are other July recaps:

July 2020

July 2019

July 2018

July 2017

July 2016

July 2015

July 2014

 

 

 

 

 

June Weather Recap: Two 4-Day Heat Waves Make June 2021 One of NYC's 10 Hottest

 

With a scorching high of 98° on the last day of the month (along with a heat index of 106°), June 2021 became New York's ninth hottest June.  This was Central Park's hottest temperature since 2013, and the hottest reading in June since another 98° high in June 1994.  6/30 was also the last day of the month's second four-day heat wave, which was just the second time there were two heat waves of this length (or longer) in June (the other was in June 1943, the hottest June on record). 

 

The month's eight days with 90+ highs were the most in June since June 1991 (which had nine).  Only four Junes have had more hot days: 1943 (11), 1966 (10), 1925 (9) and 1991 (which was slightly cooler than June 2021, ranking as 14th warmest).

 

The month had nine days with lows in the 70s, tying it for ninth most in June.  The month's five days with lows of 75° or warmer was the most since there were six in June 1943.  (June 1909 had the same number as this June.)  Finally, in the years since 1940, the low of 76° on 6/6 was the fifth earliest date for a low this warm.

 

Ironically, despite the month's warmth, this June had the latest occurrence of a reading in the mid-50s since 1995, occurring on 6/23 (54°).  This was the coolest reading of the month (twelve degrees below average).

 

The month's two four-day heat waves were three weeks apart - June 6-9, and June 27-30.  The first heat wave averaged a high/low of 91°/74° (13 degrees above average), the second was 94°/75° (nine above average).  Both heat waves had a day with significant rainfall at night, 0.47" on 6/8, and 0.65" on 6/30.  Without these heat waves, the other days of the month were one degree cooler than average.

 

Besides the high of 98°, the last day of June was also the rainiest day of the month (0.65").  If it hadn't been for this rainfall, this would have been the second June in a row with less than two inches of rain, something that hadn't happened since 1978 and 1979.  These nighttime thundershowers cooled the temperature to 73°, erasing the day's morning low of 80°.  (If that sultry low had remained the day's low, this would have been the seventh, rather than ninth, hottest June.) 

 

With eight days of 90+ readings by 6/30, 2021 joined 20 other years (since 1869) to have this many by that date (1991 had the most - 15).  The last time there was this many by this date was in 1994.  Prior to that, between 1923-1994, this many days in the 90s by the end of June occurred much more regularly, once every four years.

 

Finally, in an interesting contrast, while the last four days of June had highs in the 90s (eleven degrees above average), the last four days of May all had lows in the 40s (ten degrees below average).

 

Here are previous June recaps:

2020

2019

2018

2017

2016

May 2021 Weather Recap: Close to Average Temperature & Rainfall Despite Very Chilly & Wet End

 

Last May, the month's weather highlight was an Arctic outbreak in the second week of the month that produced the coldest reading in May (34°) since 1891.  May 2021, meanwhile, experienced one of the chilliest ends of any May, as May 28-31 tied May 1884 for the latest four-day streak with lows in the 40s.  This chilly ending was responsible for the coolest three-day Memorial Day weekend on record. 

 

Despite the month's chilly ending, an extended period of above-average temperatures from May 15-27,  that was six degrees milder than average, kept the month close to average, temperature-wise.  And a very wet May 28-30, in which 2.57" was measured, balanced what, up until then, had been a dry May (these three wet days had as much rain as the previous six weeks).  So, when all was said and done, the month was very close to average on both the temperature and rainfall fronts (-0.3 degrees, and +0.40").

 

Before May's chilly and rainy close, six days in the 10-day period between May 18-27 had highs in the 80s.  This included highs of 89° and 88° during the weekend of 5/22 and 5/23; by contrast, the following weekend had highs of 51° on both days.  This reading (which was eight degrees colder than the average low for these two dates) tied a record for the coolest high on 5/29, and set a new record (by four degrees) on 5/30.

 

Besides the last four days of the month, which were 13 degrees cooler than average, there was an eight-day period from May 5-12 that was five degrees below average.  (However, the chilliest reading of the month, 42°, was on 5/1.)

 

Finally, the last six days of the month all had measurable precipitation, the longest rainy streak since one of eight days in May 2019 (5/10-17).  However, this year's streak had a touch more rainfall (2.68" vs. 2.56").

 

Here are recaps of the previous six Mays:

2020

2019

2018

2017

2016

2015

 

April 2021 Weather Recap: Above Average Temperatures, Below Average Rainfall.

 

 

April 2021 featured ten days with highs of 70° or warmer, the first time April reported this many since 2010, and just the tenth time overall.   (The average number of such days in April is six.)  This above average number of warm days resulted in the month's average high being 2.5 degrees milder than average (its average low was 0.7 degrees above average).  Of the ten Aprils with ten or more highs of 70° or warmer, just four rank among the ten mildest Aprils.  This April ranked 22nd (out of 153). 

 

 

The month's  coldest temperature was 28° (on 4/2), which was the coldest reading in April in five years.  And although this April was significantly milder than April 2020 (which was 2.7 degrees colder than average), its coldest temperature was eight degrees colder.  The warmest reading was 85°, which is close to what the warmest reading in April has averaged since 2000 (last April was an exception, with a mildest reading of just 68°).   This reading came five weeks after the year's first reading in the 80s (82° on 3/26), and it was the warmest reading since Sept. 5.  

 

The month's warmest reading was on 4/28, but the most above-average period of the month was the seven days between April 4 and 10, when temperatures were eight degrees above average (high/low of 68°/49°).  In total, the month had twelve days that were five degrees or more above average, and five that were five degrees or more below average.  

 

Another highlight of the month occurred on 4/8 when the humidity dropped to 7% during the afternoon - the second lowest level this century.  Finally, April's rainfall of 2.69" was nearly two inches below average.  All but 0.05" fell between 4/11 and 4/30.

 

Here are April recaps of the past five years:

2020

2019

2018

2017

2016

 

How "Back-Door" Cold Fronts Impact New York's Springtime Weather

 

 

For the most part, cold fronts move from west to east in the Northeast, but, occasionally, chilly air arrives from the opposite direction.  When it does, this occurrence is known as a "back-door" cold front.   Because such a front's winds usually come off the ocean, this type of front is often associated with overcast skies (sometimes with drizzle); its east-northeasterly winds bring damp and chilly air. 

These incursions of chilly air that come from the opposite direction occur mostly in the springtime, when their cooling effect is enhanced by the wintertime water temperature of the Atlantic Ocean.  In terms of geographic reach, these fronts mostly impact New York City, the Jersey shore, and New England; only occasionally do they extend as far inland as Philadelphia, Baltimore, or DC.

What follows are 40 instances of the more impressive back-door fronts that have come down from the cold Atlantic.  As you'll read, six of the years had two notable back-door fronts.

 

June 4, 1895 - Winds shifted from the southwest to northeast during the afternoon, breaking a five-day heat wave (its record highs on June 1, 2 and 3 are still standing).  Between 3PM and 8PM, the temperature dropped from 91° to 64°.  The following day would be overcast, with temperatures stuck in the 60s. 

April 25, 1915 - This date experienced, perhaps, the greatest temperature swings of any in New York's weather history.  After the temperature soared from 47° shortly after midnight to 91° at 3:00 PM, winds shifted to the east-northeast, and the temperature plunged to 52° by midnight.  This was the result of a strong warm front moving through for about ten hours (9 AM-7 PM), then being displaced by a back door cold front.  No rain was produced by the passage of these fronts.  Two days later, a similar scenario unfolded.  After reaching 92° shortly before 4:30 on 4/27, a back-door front moved through a few hours later, and the temperature dropped to 54° by midnight.

April 1, 1917 - In the span of just eight hours, the temperature plummeted from 83° to 44° as a back-door cold front moved through, and winds shifted from the southwest to the northeast.  This was the warmest reading of the month, with the next reading in the 80s not occurring for another seven weeks.

March 19, 1918 - After a balmy high of 76° was reached at 3 PM (a record for the date that still stands), the wind shifted from the southwest to the northeast, and the temperature dropped like a rock, and was half that reading by midnight.

May 23, 1925 - After the high reached 91°, winds shifted from the southwest to northeast late in the afternoon, and by midnight the temperature had fallen to 59°; the temperature on the afternoon of 5/24 was only in the upper 40s.

July 1, 1933 - After a high in the low 90s, a severe thunderstorm from 8:30-10:30 PM dumped 2.17" of rain.  During the storm the temperature dropped from 88° to 72°, where it stayed for much of the next 24 hours.  And on 7/3, afternoon temperatures got no higher than the mid-60s.  

March 27, 1939 - Today's high/low of 73°/39° followed one of 72°/39° three days earlier.  However, while the low on 3/24 was in the pre-dawn hours, the low today was at midnight after winds shifted to the northeast in the PM hours.  And the following day had temperatures in a narrow range of 35°-40°.

April 25, 1939 - After rising from 53° at 4 AM to 86° for a few hours in the early afternoon, winds shifted to the northeast mid-afternoon and the temperature dropped back to 52° by 11 PM.  And then, three days later, the high would be only 46° (20 degrees below average).

July 4, 1941 - Just two days after a torrid high/low of 98°/78°, and winds out of the southwest, today was rainy, foggy and cool, with winds from out of the northeast, and a high/low of just 64°/62°.  Today's high would be July 4th's coolest until 1978.

 

  

March 22, 1945 - In the midst of the very mild second half of March, today was an outlier as the high reached only 40° (the low was a seasonable 35°).  Winds were out of the northeast, skies were overcast and light showers fell throughout the day. 

April 13, 1955 - A chilly high of 46° came just two days after a high of 84°.  Skies were overcast and winds were from the northeast.

July 6, 1956 - Although yesterday was cool (high/low of 66°/58°), today was even cooler, as the high/low was just 61°/57° under gray skies and winds from out of the northeast.  These two unseasonably cool days followed consecutive days in the 90s.

June 1, 1959 - Today's chilly high of 64°, under mostly overcast skies, followed a five-day warm spell at the end of May that had highs averaging 87°.  Today's conditions were the result of a back-door cold front that moved in from New England last night. 

April 30, 1962 - After three days of summer-like warmth (highs of 91°-89°-80°), and winds from out of the southwest, winds shifted to the northeast after midnight and daytime temperatures were only in the mid-40s. 

April 19, 1964 - The day after the high reached 86°, a "back-door" cold front moved through, and by mid-afternoon the temperature dropped into the mid-50s.  (And on 4/21 the high would be just 44°.)

May 5, 1965 - The day after the high reached 90°, today's was 62°.  Winds were from a north-northeast-easterly direction.

April 28, 1966  - It was a dreary, raw, and damp day, with light rain in the morning.  With a high/low of only 42°/39°, today had the coldest mean temperature of the month.  On 4/26 the mercury dropped from 73° late in the afternoon, to 49° by midnight.  Then the high/low the next two days was 52°/40° and 42°/39°.  Winds were from out of the north-northeast.

April 20, 1972 - The temperature at 4 PM was a quite chilly 43°, a drop of 32 degrees since midnight, and forty-three degrees from yesterday afternoon's 4 PM reading of 86°.  This was a result of winds shifting to the northeast from dawn to dusk.

May 24, 1975 - Today's high of 93° (the Saturday of Memorial Day weekend) was the year's first reading in the 90s.  However, the heat was short lived as a cold front from the northeast moved through during the evening, dropping the temperature to 61° by midnight, and into the upper 50s by the following afternoon. 

 

Aug. 11, 1979 - The day following a high of 95°, today's temperatures in the afternoon were only in the mid-60s after the wind shifted to the northeast during the morning.  The next day was equally cool (after a chilly AM low of 57°) - and  a wet one, as 1.68" of rain fell; this was on top of 0.87" of rain that fell the night of 8/11. 

March 29, 1985 - This was the third day in a row with exceedingly mild temperatures, and today was the warmest of the three with a high of 82°.  Then a back-door cold front moved through after dark, and by midnight the temperature was down to 55°, on its way to down to 46° by daybreak on the 30th (but still well above average).  

April 19, 1985 - After the temperature soared to 88°, a back-door cold front moved through during the evening, and the temperature was down to 51° the next morning.  Then the cool air retreated on the 21st, and after two more days with highs in the 80s, winds backed around and came from the east late in the afternoon on the 22nd, cooling the temperature down to 53° by midnight.  

March 30, 1989 - After the wind shifted to the northeast, the temperature fell all day, from 76° to 50°; the next day the high/low was 50°/41°, which wasn't far from seasonable, but it was quite a cool-down from 3/29's high of 82°.

March 14, 1990 - One day after Central Park recorded its earliest 80-degree reading on record, the warm front that delivered this extraordinary warmth retreated south of the area, as winds shifted to the northeast, and by afternoon, under a bank of clouds and fog, temperatures tumbled into the mid-40s, forty degrees colder than yesterday. 

May 23-25, 1992 - It was a Jekyll & Hyde Memorial Day weekend.  Saturday had mid-summer conditions, with a high of 92°.  Then a big change came on Sunday as a strong cold front pushed through in early afternoon, and temperatures plummeted from the low 80s to 45° by midnight.  Monday felt more like October, with overcast skies and a high of just 61°. 

April 12, 1996 - The high reached 80°, and then winds shifted to the northeast late in the afternoon, dropping the temperature to 55° by midnight, and 45° by daybreak on the 13th.

May 10, 2000 - After three days with highs in the 90s, winds shifted from the southwest to the east, bringing in much cooler air, and by daybreak today, the temperature was in the mid-50s, where it stayed for the rest of the day.  

June 12, 2000 - One month after a back-door cold front cooled down a hot spell, it was replicated today, with late afternoon temperatures in the upper 50s, and winds coming from the east-northeast, 24 hours after temperatures were in the low 90s.

 

 

April 16, 2003 - After peaking at 88°, winds shifted to the northeast and by midnight the temperature was down to 51°.  And on the 17th temperatures fell slowly all day, and it was 36° at midnight.  Winds remained out of the east-northeast for the next six days.

May 14, 2004 - The day after the high reached 86°, the temperature was only in the low 60s in the early afternoon.  However, the wind shifted later in the day and temperatures were back into the mid-80s on 5/15.

April 20, 2006 - Today's high of 83° was the warmest reading of the month.  A back-door cold front moved through during the evening, and by midnight the mercury had fallen to the mid-50s, and the mercury was mostly in the 50s for much of the next day, and stuck in the 40s on 4/22 as a developing nor'easter moved up the coast .

April 29, 2009 - The day after the high reached 90° (and dropped 25 degrees by midnight after winds shifted to the north-northeast), the temperature was in the mid-50s by daybreak.

July 19, 2012 - After yesterday's extreme heat (high of 100°) and humidity, today's high, under mostly overcast skies, was just 76°.  Never before has there been such a drop-off in temperature the day following a reading in the triple digits.  The next day the temperature was around 70° during the afternoon. 

May 28, 2014 - One day after a sultry high of 86°, today was overcast, with afternoon temperatures only in the upper 50s.  The back-door cold front passed through after 10 PM, and the temperature quickly dropped into the low 60s, then gradually falling into the 50s by daybreak, where it stayed for the rest of the day. 

June 1, 2015 - After a week of temperatures in the summery mid-80s, today was 30 degrees colder, with periods of rain, drizzle and fog.  Today's high in the 50s was chillier than any day in May - the first time this has ever occurred.  And tomorrow would have similar conditions. 

May 20, 2017 - An early, three-day heat wave came to an end last night after a shift in wind direction.  Today's afternoon temperatures were in the low 60s, which was about 30° cooler than the highs of  the previous three days.

Nov. 4, 2017 - The day after temperatures were in the mid-70s, the temperature at daybreak today was nearly 30 degrees chillier, the result of a shift in the wind direction; afternoon temperatures were twenty degrees cooler.  On the positive side, skies were mostly clear.

April 8, 2019 - After peaking at 79° at 4 PM, winds shifted from west to northeast, and by midnight the temperature was down to 49°.

October 3, 2019 - The day after the mercury soared to 93° (the first reading in the 90s in October since 1941), winds shifted overnight to a northeasterly direction, and temperatures this afternoon were only in the mid-50s.  Light showers and drizzle fell throughout the day.

 

 

 

 

 

 

March 2021 Weather Recap: Mild & Rainy Last Two Weeks

 

 

The first week-and-a-half of March 2021 was exceedingly dry, with just 0.16" falling thru St. Patrick's Day.  (3/1 was the only day with rain.)  Then, in the last two weeks of the month, regular rainfalls returned, with 3.25" measured (more than 50% above average for that period).  The beginning of the month was also on the cold side, with temperatures four degrees colder than average through the 8th (the coldest day was 3/2, with a high/low of 33°/21°).   The rest of the month was six degrees above average, largely due to the last twelve days of the month, which were nine degrees milder than average (high/low of 64°/45°).  Overall, the month was 3.3 degrees above average, and was the 13th mildest March on record (March 2020 was eighth mildest).   The average high was 4.4 degrees above average; the average low was 2.3 above average.

 

The month's highlight was the record high of 82° on 3/26 – the first reading in the 80s in March since 1998 (and the eighth year in which the first 80+ occurred in March).  Besides this first reading in the 80s, March also had the year’s first readings in the 60s (3/9), and 70s (3/11).  This was just the third year in which all three occurrences happened in March, joining 1945 and 1977.

 

 

For the second year in a row, there was no measurable snow in March, just the second time this has happened; the first time was in 1945 and 1946.  And for just the fifth time, February, which was one of the snowiest, was bookended by a January and March with little snowfall.

 

There were eight days that were ten or more degrees milder than average (including 3/26's high of 82°, which was 29 degrees above average), and two others that were more than ten degrees colder than average.  14 days were five degrees or more above average (including eight in a row, from 3/21-3/28, that were seven or more degrees above average); eight were five degrees or more below average.

 

After back-to-back months with diurnal variations below ten degrees, March's was 16.6 degrees (average is 15.1).  Additionally, the range between the coldest and highest temperatures in March was 61 degrees (21° and 82°), the widest range since 2007, when it was 67 degrees (11° and 78°).  This was in contrast to January and February, both which had variations of only 37 degrees. (The greatest range in March is 72 degrees, which was in 1990, when the temperature extremes were 13° and 85°.) 

 

The month had fifteen days with humidity levels that dropped to 25% or lower at some point in the day (usually in the afternoon), with the lowest being 12% on 3/15 at 4:00 PM (and there were two other days with lowest humidity at 13%).  Finally, ten days had a peak wind gust of 35 mph or higher, with the peak gust at 44 mph, which was clocked during the evening of the 26th (the day with a high of 82°).   

 

Here are March recaps from the five previous years:

2020

2019

2018

2017

2016

 

 

 

 

Marches of 19th Century Were Far More Wintry Than They Are Today

 

Of all the months of the year, March has warmed up the most since the 19th century (1869-1900).  While the average annual temperature so far this century (thru 2020) has been 3.6 degrees warmer than the average annual temperature in the late 19th century, March is 6.3 degrees warmer (April is next, at +5.2 degrees).  In the 19th century, March's average temperature was 36.5°, which would be considered quite cold for March of recent times (and more typical of what February's average is); the last time it was that cold in March was in 1984.  (March 2018 was a cold one by today's standards, with an average temperature of 40.1°). 

 

Eight of the coldest Marches on record are from the 19th century (and 18 of the 25 coldest).  Additionally, 16 current record lows in March are from the 19th century, as well as 15 record-low highs.  (One outlier is March 5, 1880, which had a record high that is still in place.)   Five of the six Marches with the the most highs of 32° or colder fell between 1875-1896.

 

Eleven daily snowfall records established in March during that century still stand today.  The first, third and tenth snowiest Marches occurred in 1896, 1888 and 1890.  But of all of the snowstorms of one foot or more that the City has had, just one was from the 19th century - the Great Blizzard of 1888 that buried the City under 21".  (And for nearly 60 years it was the biggest snowstorm of all time; it's now the City's fourth greatest snowfall).

 

 

Ten of the thirty-two Marches had at least one reading in the single digits (for a total of 16).  Since then, just five other years have had it happen.  The last time was in 1967.  The frequency of such frigid March readings dropped from once every three years, to once every generation (24 years). 

 

Here are wintry highlights of the cold Marches of the late 19th century:

March 1, 1869 - High/low of 26°/4°.

March 14, 1870 - This was the fourteenth day in a row with highs of 40° or colder (the average high was 34°); six of the days had highs of 32° or colder.  9.5" of snow fell during this two-week period.  And March 17 was the sixteenth day in a row with a low temperature in the teens or 20s.

March 5, 1872 - This morning's low was 3°, the coldest reading ever experienced in March.  This was the second of three days in a row with lows in the single digits, the most of any March.  This is the third coldest March on record.

March 21, 1872 - High/low of 27°/14° on the first full day of spring. 

March 20, 1875 - An ice storm on the first day of spring dropped 0.54" of liquid precipitation in temperatures that were below freezing all day (high/low was 31°/22°).

March 23, 1875 - Five of the past six days had highs of 32° or colder.  Average high/low during these six days was 31°/18°.

March 18-19, 1876 - Lows of 9° on both days.

March 10, 1877 - The day after the mildest reading of the month (57°), the temperature at daybreak was 21°.  This was the first of eleven days in a row in which there were no highs milder than 40°; four days in a row would see lows in the teens (coldest reading was 10° on 3/19).  The average high/low during this very cold outbreak was 32°/22°.

March 19, 1877 - Yesterday's and today's frigid highs and lows of 26°/12° and 22°/10° were comparable to the Arctic cold experienced on the same two dates the previous year (30°/9° and 27°/9°). 

March 12, 1883 - This was the tenth day in a row with highs colder than 40°.  High/low during this time was 33°/17°.  Two snowfalls during this streak amounted to 5.5".

March 30, 1883 - A snowfall of 4.5" was the sixth snowfall of four inches or more this winter (none occurred in December).

March 1-5, 1884 - The month began with five days with highs of 30° or colder, with two reporting highs of 21°, and one, a high of 18°.  Average high/low during these days was 23°/12°.

March 30, 1884 - It was a very late date for a sub-freezing high temperature (31°) at a time of the month when the average high was around 50°.

March 18, 1885 - Today's low of 8° was the 18th in the single digits or colder this winter, breaking a tie with the winter of 1872-73 for most on record (later passed by the winter of 1918, which had 20 frigid lows).

March 24, 1885 - This was the eighth day in a row with lows in the teens or colder.  The average low during this stretch was just 13°.  (March 1885 is the second coldest on record).

March 21, 1887 - Today's high of 49° was the mildest reading this March - the only March with its mildest reading below 50° (it would happen a week later as well).  By comparison, January and February each had a reading in the low 60s.

March 29, 1887 - The temperature fell slowly throughout the day, from 29° shortly after midnight to 19° nearly 24 hours later.

March 2-25, 1888 - Thirteen of the days had highs of 35° or colder, and fourteen had lows in the teens or colder.

March 12, 1888 - The Blizzard of '88 (also known as the Great White Hurricane) roared into an unsuspecting New York during the morning and brought the City to a standstill for the next few days.  16.5" of snow fell today, with an additional 4.5" falling tomorrow into the early morning hours of the 14th.  This was New York's biggest snowstorm until Dec. 1947 (it's now ranked fourth).  In addition to the large amount of snow, the storm's danger was magnified by mountainous snow drifts created by winds that gusted between 45 and 55 mph, and extreme cold, as the temperature dropped from 33° to 8°.  

March 13, 1888 - A bit more snow (three inches) fell today from the blizzard that arrived yesterday, but what stood out  was the extreme cold (even by mid-winter standards), as the high/low was just 12°/6° - the second coldest day ever experienced in March (the high/low on March 5, 1872 was 10°/3°).  With gusty winds still prevalent, wind chills were below zero.  This was the fourth March in the 1872-1888 period to have two or three days with lows in the single digits; since then it's happened in just one other year (1916).

March 19, 1890 - A late-season snowfall of six inches was the largest accumulation of the winter, beating the snowfall of Dec. 14 by half an inch.  March 1891 had four snowfalls of three inches or more; they totaled 17.1", which is the tenth greatest accumulation for the month.

March 2, 1891 - The morning low of 9° was the coldest reading all winter.  This was similar to last year when the only reading in the single digits was also in March (7° on 3/7). 

March 18, 1892 - Snow that began falling late last night continued through this morning, accumulating eight inches (the 7.2" that fell today is the most to fall on 3/18).  This was the biggest snowfall of the winter (passing a six-inch snowfall on 1/16) and came in the midst of an unseasonably cold 12-day stretch (March 11-22),  in which the high low was a cold 34°/22°.

March 15-16, 1896 - Less than two weeks after a snowfall of ten inches on March 2, an even bigger snowstorm dumped a foot of snow.  (And in between these two storms, four inches fell on 3/12.)  It began early in the afternoon of the 15th, and by midnight 6.5" had accumulated; an additional 5.5" fell the next day through midday.  Then the snow changed to rain as the temperature rose into the mid-30s.  Then on 3/23, 4.5" fell, bringing the month's total snowfall to 30.5".  This would be Central Park's snowiest month until Feb. 2010, and is now ranked third (Jan. 2011 also had more).  High/lows were 28°/15° on 3/24 and 32°/23° on 3/27.

March 11-18, 1900 - Lows were 22° or colder for eight consecutive days.  The average for these days was 16°.

 

 

 

A Taste of Summer: The Year's First High of 80+

 
Since 1980, the average date of the first reading of 80° or warmer is April 21 (a month later than the average date of the first reading of 70°+).  This is about a week earlier than 1900-1979, and two weeks earlier than the 1869-1899 period.  It's happened as early as March 13 (in 1990) and as late as June 7 (in 1924).  1918, 1927, and 2010 had their first reading of 80+ occur on the same date as each year's first high in the 90s. 

 

The average high temperature on the day before the first 80+ reading has been 70°, on the day of the first 80+, it's been 83°, and the high on the day following has averaged 74°. 

 

About one-third of the years have had a day of 80° or warmer on the day following the first 80+, but 16 years didn't have their second high of 80°+ for four weeks or more.  The greatest number of days to elapse before the second 80+ reading was 57 in 1928 (April 6-June 1).  The most recent lengthy hiatus was 41 days in 2013 (April 10-May 20).

 

Eight years have had their first 80+ high in March.  The first time it happened was in 1921, the most recent occurrence was 100 years later, in 2021.  Meanwhile, a first 80+ in June has occurred just once (1924).

 

 

On the day with the first high of 80° or warmer, the diurnal variation has averaged 27 degrees (this compares to a 14-degree variation for any day of the year).  The  greatest variation was 43 degrees in 1929, when the high/low was 89°/46°.   The smallest variation was 16 degrees in 1908 (81°/65°).

 

 

The chilliest low on the day of  the first 80+ reading was 43° in 1936 and, again, in 1990.  The warmest low was 68° in 1898.  The chilliest day-before high was 49°, in 1977.  The chilliest day-after high was 50° in 1921, and 51° in 1939.

 

29 years (about once every five years) had a warmer reading on the day after the first 80+ reading.  The warmest day-after reading was 93° in 1988.   The last time the day-after was warmer was in 2009, when the  high was 92° (the first 80+ reading that year was 88°).  The warmest day-before reading was 79°, which has happened in four years, most recently in 1955.  (And ten other years had a day-before high of 78°.)

 

April 19 is the date that's had the most first 80+ occurrences - in ten years.  And it's happened in seven years on April 25.   The most consecutive years to have the first 80+ occur in May is six, from 1873-1878. 

 

There have been six pairs of years in which the date of the first 80+ was the same:

> April 18, in 2015 and 2016

> April 15, in 2002 and 2003

> April 19, in 1972 and 1973

> April 26, in 1969 and 1970

> May 16, 1931 and 1932 (and in 1933, the date was 5/15)

> April 19, in 1914 and 1915

 

There have been fiver pairs of years in which the dates of the first 80+ were at opposite ends of the early/late spectrum.

> 1997 - May 19/ 1998 - March 27

> 1988 - May 23/ 1989 - March 28

> 1984 - May 23/1985 - March 29

> 1945 - March 20/ 1946 - May 25

> 1920 - May 28/ 1921 - March 21

 

Finally, measurable rain has fallen on the day of the first 80+ reading in 20% of the years (similar to the day of the first reading of 70+).  The biggest rainfall on this date was 0.67" in 1984 (May 23) as afternoon thunderstorms moved in after the temperature peaked at 81°; the second most was 0.60" in 1951 (4/29).