New York City Weather Archive

Today in New York Weather History: August 18

 

1919

More than twelve inches of rain fell in the past five weeks.  During this period measurable rain fell on twenty-two days.  Today's rainfall was the fifth rainstorm of an inch or more.  Besides significant rainfall today (1.74") today was also very cool with a high/low of 65/63.

1943

Today's high of 79° was the first since July 7 that was below 80°.  The average high during this nearly six-week period was 87.4 degrees (with 14 days in the 90s).  This streak of 41 days surpassed the previous lengthiest streak of 37 days in 1917.  However, it would be the record holder for only one year.

 

1979

Over the past eight days temperatures were nearly eight degrees below average.  Today's high was just 68°, fifteen degrees below average.  Before this cool-down temperatures had been 4.4 degrees above average for the previous four weeks. 

1987

For the second day in a row the high was 94°, eleven degrees above average.  It was the 22nd, and last, 90-degree day of the summer.   

1988

This was the twenty-first day in a row with above-average temperatures.  During these three weeks twelve days had highs in the 90s; the average high/low was 91/76, seven degrees warmer than normal.

2009

A quick-moving, but severe, thunderstorm struck shortly before 10PM and produced a micro-burst that downed more than 500 trees in Central Park and Riverside Park (between West 90th and 106th Streets) - the most destructive storm in the history of these storied parks.  0.64" of rain fell during the short-lived storm.  Besides the violent wind and rain, the storm was noteworthy for its vivid lightning and booming thunder.  (Photo taken by Melissa Hersh from her rooftop at 106th St. & Riverside Drive.)

 

 

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Cooling Thunderstorms Prevent July 2019 From Ranking Among 10 Hottest Julys

As July 2019 came to a close it appeared the month was about to join three other Julys from the 2010s ranked among New York's ten hottest Julys.  As late as 3PM on 7/31 the day's high/low was 87/76, and if that low temperature held  the month would have tied July 1966 as ninth hottest (both with average temperatures of 79.66°).  But then mid-afternoon thunderstorms erupted between 3-4:30 and the temperature tumbled to 70° - making it the day's new low.  This brought July 2019's average temperature down to 79.56°, pushing it to eleventh place, 0.05 degree cooler than July 1949 (79.56° vs 79.61°).  However, as a consolation prize, July 2019's average low was warm enough for it to rank fifth in this category. 

 

Other observations:

• Besides the thunderstorms of 7/31, thunderstorms on 7/17 and 7/22 also resulted in lows that occurred in the evening.  Much of the month's rain fell from these two rainstorms, with 2.33" falling on 7/17-18 and 2.19" on 7/22-23.  So far this year these are 2019's two biggest 24-hour rainfalls.  And with 5.77" measured July 2019 became the second rainiest of the fifteen hottest Julys.  This was after just 0.08" of rain fell in the first ten days of the month.  (Last July, which had nearly seven-and-a-half inches of rain, also started out dry, with just 0.24" measured in the first eleven days of the month.)

 

 

• There were ten days in July with highs of 90°+ (average is eight), making it the sixth July of the decade to have this many, the most of any decade.

 

 

• This July joined 36 others that have had ten or more days with highs of 90°+.  However, July 2019's ten torrid days had the "coolest" average temperature, tied with July 1887 (91.7°).  July's hottest temperature, 95° on 7/20 and 7/21, was one of the coolest readings for hottest temperature among the Julys with ten or more 90°+ days; those other months' hottest readings averaged 99.4° (half of them had hottest readings in the triple digits).  But the average low on July 2019's hot days, 74.9°, was warmer than 24 of the 36 other Julys. 

• July 1's low of 65° was the "coolest" reading of the month.  Only July 2008 has had a warmer "coolest" reading (66° on three dates).  The month had two days with lows in the 80s, which were the same two days that had highs of 95°.  It joined ten other Julys that had two or more lows in the 80s.  Lastly, this was the unprecedented tenth year in a row in which July had no readings in the 50s.

• What was notable about July 2019 was its consistent warmth but absence of extreme heat (excluding heat indexes).  26 days had highs of 85° or warmer, one shy of the July record, which has happened in three years: 1944, 1966 and 1993 (the average number of such days is 17).  Additionally, 24 days had lows of 70° or warmer, the second most on record; only July 2010 had more, with 25 (the July average is 15).

• I refer to the week of 7/16 as as New York's "Hell Week" because, historically, it is the week most likely to have readings of 90° or hotter.  And this year six of July's ten 90-degree highs were concentrated during this week.  The one day not in the 90s, 7/18, was stuck in the 70s all day (high/low of 79/71) due to overcast skies and northeasterly winds.  Ironically, 7/18 has been the date most likely to have a high in the 90s/100s.

 

 

• July was the third month in a row with more than five inches of rain, joining three other years which had five or more inches in May, June and July (1984, 1989 and 2009).  Although the 18.05" that was measured was nearly five inches above average it was significantly less than what fell in the other three years.

 

 

• Finally, for the fifth year in a row 4th of July had a warmer high than the previous year.  And with a high of 90°, this year's was the hottest 7/4 since 2012.

 

Here are recaps for the five previous Julys:

July 2018

July 2017

July 2016

July 2015

July 2014

 

 

Recap of June 2019's Weather in New York

June 2019, like June 2018, was 0.2 degrees above average (this followed a May that was 0.2 degrees below average).  However, this June's average high was 0.6 degrees cooler than last June while its average low was 0.6 milder.  The first half of the month was 0.7 degree cooler than average while the second half was 1.2 degrees warmer.  Similar to last June the warmest period came at the end of the month, with the four-day period between 6/26-29 six degrees above average (high/low of 89/72); this included the year's first high in the 90s (91° on 6/29, a month later than usual).  Although the month was average in the temperature department rainfall was an inch above average (5.46"), making this the rainiest June in six years.  The biggest daily rainfall was 0.86", which happened twice, on 6/2 and 6/25.  On both dates the rain poured down in less than an hour.  Here are a few other highlights:

 

• Besides the year's first reading in the 90s being a month behind schedule, the year's first low in the 70s, on 6/25, was three weeks later than usual.  It was the first of five days in a row with a low in the 70s (6/30 looked to be the sixth but the temperature dropped to 69° as midnight approached).

• Father's Day and Gay Pride Day both were seasonably warm (high/low of 80/65 and 83/69) but Gay Pride Day had more sunshine.  Both days saw a shower, but the shower that fell on Gay Pride Day (0.06") was more disruptive because it fell mid-afternoon during the parade (the first rain to fall during the parade in eleven years) while the shower on Father's Day (0.04") was shortly before daybreak. 

• May and June had 12.28" of rain, making this the 11th wettest May/June combo on record. The 10 years with more all occurred in the years since 1948.  (Greatest amounts were 19.03" in 1989, 18.10" in 2013 and 17.69" in 1972.)

• 2019 became the 36th year (since 1869) to have one or fewer days in the 90s thru June 30.  (The average number is four).  And of the fifteen years (excluding this year) that had one day in the 90s during this period the total number of such days for the year averaged eleven (with 1955 and 2015 having the most, 25 and 20, respectively).

• Although the coolest reading of the month, 54°, was on 6/2, the coolest day of the month was on 6/13, with a high/low of 65/55 (eleven degrees below average).  This was the coolest mean temperature in more than four weeks.

 

Here are recaps of the previous three Junes:

2018

2017

2016

 

Junes With No 90-Degree Days

As meteorological summer gets underway (June 1 thru Aug. 31) a typical June will see two or three days with highs in the 90s.  However, about once every five years no readings this hot occur; since 1869 there have been 31 years in which this has happened, most recently in 2016 (and at the other end of the spectrum, one June in four has five or more 90-degree days, the most recent being in 2012). 

 

 

Using 90° as the cut-off for hot conditions, rather than 88° or 89°, is a bit arbitrary (and doesn't take into account humidity levels).  Nonetheless, a June with no readings of 90+ is usually results in a cooler than average June.  For example, none of the ten coolest Junes had any high temperatures in the 90s.  Additionally, the five coolest summers started out with a June with no 90-degree readings.  But not every June with no readings in the 90s is so cool.  In fact, the warmest June with no 90s was in 2014.  It was 1.1 degree warmer than average and ranks 39th warmest (out of 150).  And, surprisingly, one of the ten hottest summers, 2016's, started out with a 90s-free June.  Here are some other tidbits:

 

• The most years in a row to have a June without a 90-degree reading is three (1926-1928).  Interestingly, this streak was bracketed by Junes with five or more 90-degree highs (1923 had eight, 1925 had nine, and 1929 and 1930 each had five).  The most consecutive years in which June had at least one day in the 90s is 12 (1997-2008).

• Despite having no days in the 90s in June four years had an above average number of 90-degree days: 1955 (25); 1977 (23); 2016 (22) and 1979 (19).  The average number of 90-degree days in years that had no 90-degree readings in June has been 10 (an average year, since 1930, has had 18; before that the average was just 11).

• 11 of the 31 years with no June 90s had 90-degree readings prior to June 1, with 1977 having the most such days, three.

• 89° was the hottest reading in 12 of the years in which June had no readings in the 90s.  Three of those years had their 89° reading on 6/30 (this excludes any June that had a high of 89° on 6/30 but on other dates in June as well).  One June had it occur on 6/1, another on 6/2.  And three years had their first 90-degree reading on 7/1.

• The coolest warmest reading in June is 81°, occurring in 1903 (the coolest June on record).

 

 

• June 2016 and 1955 had the most readings between 85°-89°, ten.

• Finally, daily low temperatures in the 70s are sometimes considered the counterpart of highs in the 90s.  Interestingly, 22 of the 31 Junes with no 90s had lows in the 70s (nine had some lows of 72° or warmer).  Seven of these Junes had three or more, with June 1869 having the most, seven.  The warmest low during a June with no 90s was 76° in 2014.

 

 

 

May 2019 Continued April's Wet Trend, But With More Rain

Like the month preceding it, May 2019 was characterized by a surfeit of rainy days.  There were 19 with measurable rain, which tied December 1972 and May 1973 for the second greatest number for any month.  (The most days, 20, occurred in July 1871 and May 1888).  However, May 2019 distinguished itself by having more rain than those other months (see chart below).  The amount that fell, 6.82", made this May the 12th rainiest on record.  Although it had one more day of rain than April (its 18 days was a record for April), nearly two-and-a-half inches more rain fell.  But despite the high frequency of rain, much of it occurred on just five days: 1.31" on 5/5; 1.32" on 5/12; 0.70" on 5/13; 0.80" on 5/29; and 0.95" on 5/30.

 

 

In addition to the well above average number of rainy days, this May will also be remembered for the damp and unusually cool conditions on Mother's Day and the two days after.  2.32" of rain fell on these three days (1.32" of it on Mother's Day) and the average high/low of 53/43 was 14 degrees cooler than average.  By contrast, the Memorial Day weekend was mostly nice,  the exception being later in the afternoon on Sunday when clouds moved in and there was an hour of heavy showers.  The three-day weekend's average high/low was 79/60, four degrees above average, and featured the warmest reading of the month, 86° on Sunday.  (The warmest mean temperature, however, occurred on 5/20, one week before Memorial Day, with a high/low of 85/66).

 

Temperature-wise, the month was average (officially, 0.2 degrees below average), with the first half of May three degrees below average while the second half was two degrees above average.  (If the chilly three-day period from May 12-14 were taken out, the month would have been 1.3 degrees milder than average.)  Seven days were five or more degrees above average while six were five or more below average.  Four days with highs in the 80s were balanced by four days with lows in the 40s, both fewer than the month's average (of seven and six days, respectively). 

 

Finally, there was an eight-day streak of rainy days (May 10-17) that had 2.56" of rain.  This was just the thirteenth eight-day steak since 1900.  Coincidentally, last May had rain on seven of eight days around the same time of the month (May 12-19), which amounted to 2.14".  And Mother's Day both years was cool (59/43 this year, 54/52 in 2018).

 

Here are recaps of the previous four Mays:

2018

2017

2016

2015

 

 

April 2019 Weather Recap

As we headed into the last week of April it appeared the month had a good chance of becoming either the fifth, sixth or seventh mildest April on record.  But when the last five days of the month averaged five degrees cooler than average, it ended up as the 13th mildest, 2.5 degrees above average (still a noteworthy achievement as it was milder than 138 other Aprils).  Perhaps a bigger highlight was the month's 18 days with measurable precipitation, the most since May 2012.  This was also the most days of precipitation of any April.  However, despite the frequent rainfall, the 4.55" that was measured was just an average amount (the month's average is 4.50").  Despite being only average, this amount was enough to make April the wettest month so far this year. 

 

The five chilly days at the end of the month were immediately preceded by a two-week period with above average temperatures (six degrees above average); this was the longest streak of above average days since one of eighteen days in late December/early January.  This mild streak included the year's first reading in the 80's, 80° on 4/19, which was Good Friday (just the fifth Good Friday with a high in the 80s); Easter Sunday cooled down to a high of 66°.  The month's coldest reading, 33°, occurred on 4/1.  (Since 2000 April's warmest temperature has averaged 85°, its coldest reading has averaged 33°.)

 

Finally, 2019's mild April came a year after the coldest April in 40 years (which followed the second mildest April on record).  Despite the disparity between the two years, April 2018's warmest temperature was two degrees above this year's (82° vs. 80°) while its coldest reading was just one degree lower (32°).

 

Here are recaps of previous Aprils:

2018

2017

2016

 

National Weather Service's Year-Round Use of 'Standard Time' Can Cause Confusion

I had been writing this blog for a number of years before learning that the National Weather Service doesn't recognize Daylight Saving Time (the period roughly between mid-March thru early November).  Instead, its reported observations throughout the year reflect Standard Time.  Because of this, weather conditions that occur between midnight and 12:59 AM during DST are reported as part of the previous day's weather observation (credited to 11:00-11:59 PM).  And the rest of each day's weather observations are reported as happening in the previous hour.

 

I discovered this quirk because I check hourly observations every day on one of the NWS sites, and during the spring, summer and first half of the fall (i.e., when DST is in effect) I noticed that rainfall and temperature for the first hour of each day was credited to the previous day.  Then when Standard Time resumed the weather conditions of each day's first hour were back to being part of that same day.

 

 

I thought that, perhaps, this decision was made over concern by the NWS about how to report conditions that occur during the "skipped" hour, i.e., when we "spring ahead" at 2AM for DST (losing the 60 minutes between 2-3AM), or when the hour between 1-2AM is repeated when we "fall back" at the start of Standard Time.  However, it turns out the reason was simpler than that as the US is a signatory of an agreement drawn up by the World Meteorological Organization calling for Universal Coordinated Time to be used as the standard (i.e., not seasonally adjusted).  However, I can't help wondering why local weather records shouldn't reflect the time that its population is conducting its life in.  And it's curious that Standard time, which lasts about four months in much of the US, is the year-round standard.

 

 

 

So what does this mean in practice?  Let's say that a rainstorm at 12:30 AM DST on May 10 kept you awake.  Using Standard Time rather than DST, the NWS would report that the rain fell at 11:30 PM on May 9; however, in the world of Daylight Saving Time that you're living in you were watching TV at 11:30 and not in bed being kept awake by the rain. 

 

(These parallel time frames bring to mind how life was in the US before time zones were established.  Prior to their creation in 1883 there were two types of time.  True Solar Time, based on the sun's actual position over a city, was precise and used by the general public in conducting its day-to-day activities, with every city having its own time (e.g., when it was noon in NYC it was 12:10 PM in Boston, 11:55 AM in Philadelphia, and 11:50 in Washington, DC).  Railway Time, on the other hand, was used by the railroads for scheduling arrivals and departures of its trains and was the impetus for the establishment of time zones, whereby New York, Boston, Philly and DC all had the same time).

 

    

Over the course of a year there are instances of daily records hinging on what happens either during the last hour of the day or the first hour of the next day, and the DST-Standard Time situation creates a "fuzzy" reality.  For example, sometimes there are days during DST when it appears a rainfall record has been set, but using Standard time is the official measure, the amount from midnight-1AM DST is credited to 11PM-midnight, erasing what appeared to be a record amount (however, there can be instances were adding rain to the previous day could result in a record amount for that date).  Regarding temperature records, I can recall a few instances in early October during the past fifteen years when it appeared a new record for the latest date for a low of 70+ was going to be established only to find that, although the temperature dropped below 70° after midnight DST, it was actually credited to the day before, so no record was set. 

 

Of course, in the grand scheme of things, this isn't a big deal.  Since it's doubtful many people are aware of this idiosyncrasy it's a case of ignorance being bliss.  However, for those of us who are aware of this quirk it's annoying (like a hangnail). 

 

 

Here are a number of other thought pieces I'v written about weather measurement:

 

A Case For Reporting Temperature & Precipitation to One or Two Decimals

Can Trace Amounts of Precipitation Add Up to Measurable Amounts?

Why 2011, Not 1983, Should be Crowned as NYC's Wettest Year

 

 

 

 

 

 

 

Best & Worst Weather Conditions During Mets Home Openers

It seems fitting that the Mets first home opener in 1962, a season in which they lost 120 games, ranks as one of its worst, with cold temperatures, wind and drizzle.  And how perfect was it that the weather was glorious the year they won their first home opener in 1968?  The charts below focus on the best weather conditions in years the Mets won their home openers, while the worst weather is grouped into games lost and games won.  (But does it really matter what the weather is, just as long as the home team wins?)      

 

 

 

To read about weather and outcome of every Mets home opener since 1962, double click here.

 

 

 

March 2019 Weather Recap - Old Man Winter Makes a Memorable Exit

March began with a continuation of unseasonably cold temperatures that arrived in the last three days of February.  This extended Arctic outbreak persisted through the first eight days of the month; the average high/low during these days was 36/25, nine degrees colder than average.  This included three days in a row with highs of 32° or colder - the longest such stretch in March since 1984.  Besides the cold, an inch or more of snow fell on each of the first four days of the month - the longest streak of its kind.  The 10.4" that fell more than doubled the amount of snow from the previous four months (10.1"), making this the fourth winter of the past five in which March was the snowiest month. 

 

After March's harsh beginning, temperatures recovered and the rest of the month was two degrees above average, with the coldest reading being 32° (on two days) - and there was no measurable snowfall.  The month's mildest reading was 75° (26 degrees above average and two degrees shy of the record for the date), which occurred on 3/15.  A second day in the 70s came two weeks later (70° on 3/30).  Overall, the month was 0.8 degree below average, making it the sixth March of the past seven that was colder than average (but of the six years, 2019 was closest to average).

 

 

Like the temperature, the month's precipitation (3.87") was also slightly below average. The biggest rainfall of the month, and so far this year, occurred on 3/21-22 when 1.43" was measured.  This rainstorm was book-ended by three days before and five days after that had unusually low humidity; the lowest was reported on 3/24 and 3/26 when a few hours in the afternoon had readings of 13% and 14%, respectively. 

 

The 11-day stretch between Feb. 26 and March 8 saw the most wintry conditions of the winter.  The five-inch snowfall on March 3-4 was the second biggest on record to fall in temperatures that stayed above freezing (the greatest accumulation in above-freezing temperatures happened last year when 5.5" fell the morning of 4/2).

 

 

Of all the Marches since 1950, March 2019 ranks among the ten with the coldest starts.

 

 

Finally, although last March was colder than March 2019 (2.4 degrees below average vs. 0.8 below average) it had no days with temperatures colder than 27°, while this March had four such days (its coldest reading was 18°).  However, this March had eight days with highs of 55° or milder while last March had only three.

 

Other March recaps:

2018

2017

2016

 

 

 

February 2019 Weather Review: Largely Uninspiring

February 2019 was one of the least interesting months, weather-wise, in a while.  In fact, it was so uneventful I was tempted to not even bother with a monthly recap.  Although its average temperature was slightly above average (+0.9 degree) it was the coldest February since 2015.  Just 2.6" of snow was measured, the smallest amount in February in seven years (ironically, the milder February's preceding it all had more snow).  And although the amount of snow was well below the average of 9.2", the month's total precipitation (3.14") was an average amount (which is 3.09").  The coldest and mildest readings of the month occurred during the first week: 11° on 2/1, 65° on 2/5. 

 

Although the month wasn't too far from average, just three days had mean temperatures that were average.  Nineteen days were five or more degrees above or below average.  There were half a dozen days with highs of 35° or colder (three were 32° or colder) and four with highs of 55° or warmer.  The mildest stretch was the six days from 2/3 thru 2/8, which were 12 degrees above average (high/low of 54/37).  The coldest temperatures were experienced at the beginning and end of the month, with the first two days 13 degrees below average (28/14), and the final three days eight degrees colder than average (35/25). 

 

 

Although only 2.6" of snow fell (during what, on average, is the snowiest month of the winter) an amount this small isn't all that rare, happening about once every four or five years.  However, the last time a February as chilly as this year's had less snow was in 2004, which was 0.4 degrees above average and had just 0.7" of snow.  Finally, the only excitement about snow this February was the 1.2" snowfall on the 12th, which was the first snowfall of an inch or more in nearly three months (since the snowstorm of 11/15).  And it fell on the date most likely to have a snowfall of one-inch+.

Previous February recaps:

2018

2017

2015

Weather Highlights of Presidents' Day (1971-2019)

Since the Presidents' Day holiday was first observed on the third Monday of February in 1971, temperatures have ranged from 3° in 2015 to 64° in 2008.  There have been three consecutive Presidents' Days with highs of 32° or colder (1977-1979) and four in a row with highs of 50° or warmer (1981-1984).  The three coldest (based on mean temperature) were in 2015 (high/low of 21/3), 1987 (32/7), and 2003 (26/14).  The three warmest Presidents' Days were in 2008 (64/40), 1976 (60/43) and 1994 (53/42).  Here are some additional findings:

 

• The biggest temperature difference between two consecutive Presidents' Days was in 2007 and 2008 when a high/low of 30/12 was followed by a high/low of 64/40.  The closest in temperature was in 2009 and 2010 when the respective highs/lows were 40/28 and 40/27, and in 1981 and 1982 when the highs/lows were 57/34 and 56/33, respectively.

• The most years in a row with lows above freezing was five, from 1981 thru 1985.  Ironically, this streak was preceded by the coldest streak, the four-year period from 1977 thru 1980.  A five-year period from 2003 thru 2007 was also quite cold.

• Three of the coldest and two of the mildest readings on Presidents' Day have fallen on Feb. 16.  Additionally, five of the seven coldest readings have occurred during the 21st century.  Furthermore, three years in a row (2015-2017) had readings that were either among the coldest or mildest (2015, coldest on record; 2016, fourth coldest; and 2017, sixth mildest).  Lastly, the consecutive years 1981 and 1982 had two of the mildest high temperatures while 2003 and 2004 had two of the coldest lows. (See chart below.)

• Measurable snow has fallen on Monday in just five years, but two of these snowfalls were major snowstorms.  In 2003 16.5" fell (and 3.5" on Sunday night) while in 1979 12.7" fell.  The other three snowfalls were in 2005 (3.5"), 2011 (3.2") and 2016 (1.4").

• The most consecutive years with measurable precipitation on Presidents Day is only two, and it's happened three times: 2018 and 2019; 2010 and 2011; and 1975 and 1976.  The most years in a row with no precipitation is six, from 1980 to 1985.

• Looking at the three-day Presidents' Day weekends, 1979 had the coldest one, averaging a high/low of 19/7 (along with a 12.7" snowstorm).  The two next coldest were in consecutive years: 24/6 in 2016 and 26/8 in 2015.  These were followed in 2017 by the mildest Prez Day weekend: 61/42; 1994 is second mildest, with a high/low of 59/39.  There have been six years in which the lows for each day of the weekend were all 32° or milder (most recently in 2017) and four in which the highs were all 32° or colder (most recently in 2015).

• Finally, Presidents' Day weekend 2018 has the distinction of being the only one that reported measurable precipitation on all three days.  At the other end of the spectrum, the most holiday weekends in a row with no measurable precipitation on any of its days is three, 1981-1983.