Lackluster Heat Waves

This post was inspired by this week's rather tepid four-day heat wave (Aug. 5-8, 2018), which had an average high of 90.8 degrees (with highs of 91, 92, 90 and 90).  Of the 66 four-day heat waves that have occurred since 1870 only one, in July 1896, had a lower average high, 90.3 degrees.  (2018's low-grade heat wave matched one in August 2009.)  On average, four-day heat waves have had an average high close to 94°.  (The hottest four-day heat wave on record took place in the summer of 2010, when the high temperature from July 4-7 was 99.5 degrees.)

 

 

 

 

However, the story changes when low temperatures are included in the analysis.  For example, this August's heat wave had an average low of 75.0 degrees, which was 1.3 degrees warmer than the average four-day streak and warmer than two-thirds of the four-day heat waves examined.  When combined with the average high, the mean temperature ranked as 27th coolest - quite a difference in ranking compared to its average high alone.  (This follows the weather storyline of this century whereby nighttime temperatures in New York are warming more than daytime temperatures.)

 

 

Finally, while the typical four-day heat wave had a 20-degree difference between its high and low, this August's was 15.8 degrees apart, which was the third smallest diurnal variation of the heat waves studied (a heat wave in July 1995 had the smallest, 14.7 degrees, while the second smallest was in July 1870).  

August 2016 Passes August 2015 as Third Hottest

One year after New York sweated through its third hottest August on record, August 2016 was a wee bit hotter, by 0.2 degrees.  This margin was due to warmer nights (71.8° vs. 71.0°) as the average high of 86.6° was a bit below last year's 86.9°.  And after July 2016 was the wettest in seven years, August reverted to the dryness of the first half of the year as its 1.97" made it the driest August in twenty years.  However, what August and July had in common were cool starts as July 1-4 was 3.6 degrees below average and Aug. 1-4 was 2.8 degrees cooler than average.  Another similarity was five-day heat waves (July 21-25 and Aug. 11-15), making this the first summer since 2002 to have two heat waves that were five days or longer. 

 

Here are  further details about August 2016: 

• August had seven days in the 90s.  Interestingly, there have been twelve Augusts with ten or more 90-degree days, with all but one of them cooler than August 2016.  Why?  Like July, it was due to an absence of any sustained period of cool air.  The coolest high was 79° (on two dates), and the most below average day was just 3 degrees below average.  (August 2005, the second hottest on record, also had fewer than ten 90-degree days.)  In addition to the seven 90-degree days there were also five days with highs of 88° or 89° (all in the last two weeks).
  

 

• Aug. 13, with a high of 96/81, was the hottest day of the year, passing July 23 and its high/low of 96/80.  However, when the heat indexes of each day are compared, the two days weren't close.  Aug. 13 was very humid and the heat index reached an unbearable 110° while July 23 had low humidity, which produced a heat index that was a few degrees below the air temperature.  For five consecutive days (Aug. 10-14) dew points never fell below 70°, and during those days heat indexes remained above 90° until nearly midnight.   
  

• The 16-day streak of above average mean temperatures from Aug. 6-21 was the longest streak of the year.  Then two days after it ended a refreshing low of 61° was the "chilliest" reading since 6/18.  (Then unseasonably warm conditions returned for the final week of the month.)
  

• A very fascinating thing happened on Aug. 25, when the year's total precipitation matched exactly the amount on that date last year - 26.92" (more than five inches below average).  And this continued for a few more days.

• This August joined five others that were hot and dry.

 

• In the 12-day period from Aug. 11-22, measurable rain fell on ten of the days - but the amount that fell was a modest 1.90" (by contrast, a similar rainy stretch in the first half of Sept. 1974. saw 7.40" fall).  And much of the rain fell in just a half-hour period on Aug. 20 when 0.82" poured down during lunchtime - this was the same localized afternoon rainstorm that dumped three to five inches of rain on the north shore of Long Island.
  

 

• Both August 2016 and 2015 were hotter than July.  This was just the sixth time that back-to-back Augusts had this distinction.  And although the difference between August's and July's mean temperatures in 2016 and 2015 was minimal, this was because July of both years was well above average in temperature.

 

• Finally, July and August 2016 became the fifth hottest July-August combination on record, 0.1 degree ahead of July and August of 2015.  And this summer joined fourteen others that had two or more days with 80-degree lows, with one each in July and August.
  

 

 

The typical weather map in August 2016.

 

 

 

   

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Record Highs & Lows: The Home Runs of Weather Reporting

Because of the excitement they generate I like to think of record high and low temperatures as the home runs of the weather world.  Since weather records for New York go all the way back to 1869 it's a challenge for new ones to be set.  Still, since 2000 (thru 2018) there have been 82 records set or tied, which is about four every year (in 2018 two new record highs were established and two were tied).  However, only nine of the 82 were record lows (most recently on Nov. 11, 2017).  Here are some other interesting facts about New York's temperature extremes:

 

• The oldest-standing record is the record low of March 1 which goes all the way back to the first year of record keeping, 1869.  The oldest-standing record high occurred nearly as far back, on Jan. 23, 1874.  The newest record (thru the end of 2018) was set on May 3, 2018 when the high reached 92°.

• 22 record highs and 91 record lows stand alone, i.e. not shared with other years.  The most years tied for a record on one date is six, for record lows on three dates: March 3 (11°), June 2 (48°) and Sept. 8 (54°).  (Ties would be less prevalent if daily temperatures were reported to one decimal point.)

• There are 21 current records that broke a record set the previous year (12 for lows, nine for highs).  The most recent occurrence was in 1994 when the record high on June 19 broke the previous record set the year before.

 

 

• The most that a record beat the previous record by was 19 degrees on Sept. 7, 1881 (101° vs. 82°).  There are 31 current high temperature records that beat the previous record by 10 degrees or more.  The most recent happened on Feb. 21, 2018 when the new record high was 10 degrees above the previous record (78° vs. 68°).  Eight record lows exceeded the previous record by 10 degrees or more, with the largest difference being 14 degrees on Dec. 18, 1919 (-1° vs. 13°).

• Of the 150 years since 1869, three had no record highs or lows: 1870, 1958 and 1992.  The year with the most records was 1888 when 49 were set (38 were record lows, 11 record highs).  In recent years the year with the most records was 2001, which had 15 (14 record highs, one record low).  These figures reflect records that may no longer be valid, with many broken in subsequent years.  Looking at records that are still standing, 1888 still has the most, but the figure is 18; it's tied with 1875.  

• The mildest reading for a record low is 59°, and it has occurred twice - on July 29 (in 1914) and on Aug. 1 (1964).  The lowest temperature for a record high is 54°, which was set on Feb. 7, 1938.  

• Finally, New York's all time hottest and coldest temperatures occurred just two years apart, in 1934 (-15° on Feb. 9) and in 1936 (106° on July 9).

 

 

 

(This post was inspired by an in-depth compilation of data supplied by Eugene De Marco, another New York City weather hobbyist.)

 

 

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Summertime in New York as Portrayed by Covers of The New Yorker

Covers of The New Yorker not only capture the personality of the residents of New York but also the beauty and humor of the various seasons there.  This post looks at my favorite covers that celebrate summertime in the City, either through humor, childhood memories or the depiction of leisurely stay-vacations in the area. 

 

Sweet Relief (June 6, 1959)

 

By the Sea, By the Sea, By the Beautiful Sea (July 29, 1961)

 

Congestion on the Hudson (June 1, 1963)

 

At the Shore (Aug. 5, 1967)

 

Greeting Their Master (Aug. 24, 1968)

 

Baking (Aug. 15, 1970)

 

Above the Fray (Sept. 2, 1972)

 

El Sol (June 10, 1972)

 

Manhattan High (Aug. 13, 1973)

 

Far From the Madding Crowd (Aug. 23, 1976)

 

Not a Care in the World (Aug. 11, 1977)

 

Hazy, Hot & Humid (Aug. 16,1982 )

 

Perfect Summer Day (July 19, 1982)

 

Life's A Beach (Aug. 20, 1984)

 

Lazy, Hazy, Crazy Days of Summer (July 21, 1986)

 

UV Protection (Aug. 24, 1987)

 

Summer in the City (June 12, 1995)

 

King Kong & the Super Soaker (Aug. 1, 2005)

 

Not All Therapists Take August Off (Aug. 7, 2006)

 

Hot Fun in the Summertime (July 23, 2007)

 

I've written a similar post about my favorite wintertime covers.  Large reproductions of these covers, as well as every New Yorker cover (nearly 5,000), are available for purchase on Conde Nast's website.  (And small versions are sold by street vendors throughout midtown Manhattan.)

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January Isn't Always the Coldest, July Isn't Always the Hottest

 

A reader recently asked if there have ever been any winters in which February was colder than January.  While it's not the norm, it happens occasionally.  Actually, more often than occasionally - 57 times, or nearly 40% of all years since 1869 (and it happened last winter).  In fact, New York's all time coldest month occurred in February 1934.  Perhaps of greater interest is the fact that there have been 17 winters in which December was the coldest month, the most recent being December 2005.  But the biggest anomaly of all occurred in the winter of 1960, when March was the coldest month!

For the most part, when February and August were colder/warmer than January or July it was when January was milder and July cooler than average.  However, there were six winters when both months were colder than normal (the most recent being in 1978).  And there have been four summers in which both months had above average temperatures (most recently in 2005).

 

 

 

 

 

Today in New York Weather History: May 19

 

1962

The high temperature soared to 99°, making this the hottest reading ever recorded in the month of May.  (The temperature jumped 41 degrees in ten hours after the day's low at 6 AM.)  May's previous hottest temperature was 96°, which occurred in three years - 1880, 1939 and 1941.  Some relief occurred between 8:00 and 9 PM when a thundershower moved through, dropping the temperature from 87° to 70°.

 

1975

Seven of the eight days since 5/12 had morning lows of 58° or 59°, five degrees above average.  The one "outlier" had a low of 60°. 

 

1976

It was a raw and chilly day, more like March 19, with a high/low of only 52°/38°.  This was eighteen degrees below average.  Morning showers made the day feel even colder.

1994

A raw and damp day, with a high of only 54°, eighteen degrees below average.  The last time there was a high temperature this chilly was five weeks earlier on April 12 (when the high of 54° was just five degrees below average).

1997

Today was the only day of the month that warmed into the 80s (the high was 83°), the fewest number of 80-degree days since May 1983, which had none.  (2003 and 2005 would also have no 80-degree days.)  This lack of 80-degree temperatures contributed to making this the chilliest May in thirty years.

 

2005

Today was the second consecutive day with a high/low of 70/53° and replicated a pair of 70°/53° highs/lows on May 18-19, 1932.

2017

Today's high of 91° was the third in a row in the 90s - the first time for a three-day heat wave in May since 2001 (and the 34th year to begin its 90-degree readings with a heat wave).  Cooler air moved in after 8 PM and by midnight the temperature had fallen to 66°.  (It would then be three weeks before a temperature of 80° or warmer was reached.)

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A Look Back at New York Weather: May 8

 

1980

Today's chilly high of 56°, twelve degrees below average, came three days after a high of 90°.

1984

This was the fourth day in a row with a high temperature of 69° (one degree above average).  And three of the mornings had lows of 53° (two degrees above average).

2000

Today's high was 91°, the second day in a row with a record high. 

2011

It was a near-perfect Mother's Day, with a high of 74°, five degrees milder than average.  Bright sunshine in the morning gave way to a mix of sun and puffy cumulus clouds during the afternoon. 

2013

Nearly two-and-a-half inches of rain poured down during morning rush hour - twelve times the amount that fell in the previous twenty-five days (0.19").  Including additional showers that moved thru at lunchtime, 3.02" fell in total, equal to the amount measured during the previous eight weeks.  Manhattan was the bulls-eye for this torrential rain - the biggest rain storm since September 2011, and the most rain to fall in a 24-hour period in May since 1978.  Additionally, today's amount was a record for the date, breaking the previous one set in the 19th century.

 

2016

After having highs of 70° or warmer on the previous five Mother's Days (with four of the five in the 74°-83° range), today's was a chillier than average 65°, which made it the chilliest MD since 2010 (when the high was only 52°).  However, after a period of rain around daybreak the sun broke through late in the morning and the afternoon was sunny, breaking a week-long streak of overcast skies.  And although today's high temperature was four degrees below average, this was the warmest reading since 4/25.

 

2020

A rare springtime incursion of Arctic air moved through during the afternoon and by midnight the mercury had fallen to 36°.  This was a record for the date, the first May reading in the 30s since 1978 (38° on 5/1) and the coldest reading in May since 1966 (36° on 5/10).  Light rain fell during the PM hours, amounting to 0.45".  (It should be noted that the reading of 36° credited to today actually occurred shortly before 1 AM Daylight Saving Time on 5/9, but the NWS uses Standard Time year-round for its records.) Save

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Today in New York Weather History: April 27

 

1915

Two days after the temperature soared into the 90s, it did so again today.  But after reaching 92° shortly before 4:30 (one degree hotter than 4/25) a cold front moved through a few hours later and the temperature dropped to 54° by midnight (similar to what happened two days ago.) 

 

 

1962

In a span of 13 hours the temperature soared from 51° at 1 AM to 91° by 2 PM.

1990

Just like 1962, the day's temperature soared from 51° to 91°.  This was the earliest date for a year's first 90-degree reading since 1977 (when it occurred on 4/12).

 

1994

0.41" of rain fell during a twenty-minute thunderstorm later in the afternoon (4:27-4:47 PM).  After a cool start (low of 50°) it turned into a warm day as the high reached 82°.

 

2007

2.07" of rain, a record for the date, brought April's rainfall total to 13.05".  This was a morning rainfall, with a little more than half of the amount pouring down between 3:00 and 5:00 AM.

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Today in New York Weather History: April 25

 

1875

Less than two weeks after a snowstorm of ten inches (on 4/13), another significant snowfall dropped three more inches - despite the fact that the temperature got no lower than 34°.  This is the latest measurable snowfall on record.

1915

Today saw perhaps the greatest swings in temperature of any date in New York's history.  After first steadily climbing from 47° shortly after midnight to 91° at 3:00 PM, the temperature then plunged to 52° by midnight.  This was the result of a strong warm front moving through for about ten hours (9 AM-7 PM) and then being displaced by a backdoor cold front.  There was no rain produced by the passage of either front.  Two days later the temperature would rebound into the low 90s again only to drop like a rock after nightfall.  These crazy swings came three weeks after 10.5" of snow buried the City.

 

1919

It was a cold day, with temperatures more like winter than the middle of spring.  The high/low was just 43°/29°, nineteen degrees below average.  And tomorrow's readings were very similar (44°/31°).  Both days also had winds that gusted to 25 mph, making it feel like it was in the 30s.

1960

After a seasonably cool low of 48° the temperature rose sharply, to 87°.  Meanwhile, although they were still milder than average, yesterday and tomorrow had highs of 70°.

1962

For the third year in a row a big jump in temperature occurred on this date.  This year the mercury jumped from 48° to 84°; in 1961 it rose from 49° to 82°; and in 1960 the high reached 87° after a low of 48°. 

1976

Five days after an unprecedented four-day heat wave ended (with highs of 91°-96°-92°-89°), today was the first of three days in a row with highs only in the 40s (49°-46°-49°).  

2002

A steady rain, amounting to 0.55", fell during the afternoon - the first rain on this date in 12 years.  One week after a heat wave, with temperatures 30 degrees above average (comparable to hot temperatures experienced 1976's), today was chilly, with a high/low of 52°/43°.

 

2007

For the sixth year in a row rain fell on this date as mid-afternoon showers amounted to 0.14".

2009

What a spectacular start to my summer share at Fire Island as the afternoon high soared to 88° (in NYC) after a low of 52°.

 

2010

After just 0.61" of rain fell in the first twenty-four days of the month, 1.60" poured down today.  The rain came from two storm systems.  The first brought the bulk of the rain in the AM hours (1.13"), the second moved in after dark.

2018

It was a dreary, showery, fog-shrouded day.  The 0.95" that fell (much of it between 6-9 AM and then just before midnight) pushed April's total precipitation past the five-inch mark, the third month in a row with five inches or more.  The last time this happened was Sept-Oct 2011, but that three-month period had more than twice as much precipitation (34.43" vs. 16.45").

 

 

 

 

 

 

 

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A Look Back at New York City Weather: April 16

 

1914

This was the third day of the past six to have an inch or more of rain (and another day had 0.89").  In total 4.30" of rain fell.

1975

Today was just one degree below average, but it was the fifteenth day in a row with a below average mean temperature.  During this period temperatures were nearly eight degrees below average.  

1985

It was a glorious day for a baseball game as the high reached 75° and the Yankees beat the White Sox in their home opener on a walk-off home run in the bottom of the 9th inning.

 

1996

1.04" of rain fell between 1-4 AM and 2.19" overall (including rain from last night that fell after 9:00 PM).  Most of the rain was over by 8:00 AM.  This storm's rainfall equaled the amount of precipitation (in liquid form) from the blizzard back on Jan. 7-8.

2000

Today had the mildest reading of the month, 75°.  This was the last April with no days in the 80s, until 2014.   

2002

Today was the start of a very early four-day heat wave: 92° today; 96° on 4/17; 91° on 4/18; and 89° on 4/19.  At the time today's temperature was the third earliest date on record for a year's first 90-degree reading.  (I thought I was planning ahead and had my air conditioner taken out of my apartment yesterday to have it cleaned and serviced.)  Interestingly, there was a nearly identical mid-April heat wave back in 1976 that started one day later.  It also lasted four days and had the same four high temperatures, only in different order.  (To read more about 90-degree weather in April, double click here.)

 

2003

After the temperature soared to 88°, twenty-seven degrees above average, a back-door cold front moved through and the temperature dropped to 51° by midnight.  Today's high wouldn't be topped for ten weeks.

2007

After yesterday's 7.57" of rain an additional 0.84" fell this morning.  In total, rain fell for 36 consecutive hours.

2011

A nasty storm system moved in late in the afternoon and buffeted the area with 40-50 mph winds and 1.78" of rain, most of which fell today.  Nearly half of the rain poured down between 7-9 PM. 

2012

It felt like mid-summer as skies were sunny and the high soared to 88°.  This was the first 80-degree day of the year, not far from the typical day of New York's first 80, which is April 20.  However, it was three weeks earlier than the usual date for the first 85+ reading.  Today was also the ninth day this year with a mean temperature 20 degrees+ above average, well above the typical number for an entire year (four).  

 

2014

The morning low of 31° was the latest date for a temperature of 32° or colder since 1980, when the low was 32° on April 17.  The last time a temperature was below freezing this late was way back 1943 when the low was 30° - also on April 4/16.  Today's chilly low broke a string of six consecutive Aprils with no lows of freezing or colder, the longest streak on record.  Additionally, the dusting of snow this morning was the latest for a trace of snow since 1997. 

 

2017

This was just the seventh Easter Sunday to be in the 80s (going back to 1870), and with a high of 87° it became the second warmest Easter Sunday on record (behind 1976).  Today was also the warmest reading in April since 2012 when a high of 88° occurred, also on 4/16.  Today's high came five days after the year's first 80-degree reading.

 

2018

A rainstorm that moved in last night continued through noon today, bringing flooding rains and winds that gusted over 40 mph.  Total rainfall was 3.29", 2.82" which poured down this morning; more than half of it (1.54") fell in the three hours between 7:30 and 10:30.  This was the greatest 24-hour rainfall in four years, since nearly five inches flooded the city on 4/30 in 2014.  As today's rain exited the temperature jumped 14 degrees in the hour between 11:00 and noon (from 46° to 60°). 

 

 

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