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July 2023 Weather Recap: Consistently Warm Rather Than Excessively Hot

 

 July 30 - purple flower

 

This post may be one of the few weather-related articles that doesn't hyperventilate about hot weather in the middle of summer.  And despite New York's news media hyping the term "heat dome" any time the local forecast called for a high approaching 90°, just five days in July had highs in the 90s in NYC, and there were no heat waves; the hottest reading was just 93°.  Globally, July was the hottest month on record, but that wasn't the case in Central Park as it was the 20th warmest July (average high/low was 86.4°/71.7°, 1.5 degrees above average).  

 

Every day but one had a high of 80° or warmer (the typical number of days in July with highs cooler than 80° is six), comparable to last July which had no such days.  As for low temperatures, this July and July 2022 both reported 24 days with lows in the 70s, tying three other Julys for third most (July 2020 had 26, 2010 had 25).  Although it had a below average number of days in the 90s (five versus seven), July 2023 had an above average concentration of highs that were 88° or 89°, with ten counted.

 

July was slightly wetter than average, with 5.34" measured.  This was almost double what fell in May and June combined (which had 1.29" and 1.62", respectively).  More rain fell in the first four days of July (1.66") than what fell in all of June.  This included 0.63" of rain that fell on 7/4, the most on Independence Day since 1981 (when 1.76" fell).   

 

The month's greatest daily rainfall was 1.32" on 7/16 (0.91" of it fell between 11 AM and 1 PM); this daily total was more than what fell in all of April.  On that day, which had a low of 74°, the high reached just 78°, which is the coolest high temperature ever reported with a low this warm.   

 

Only five days had below average temperatures, all of which occurred in the second half of the month.  Meanwhile, seven days were five or more degrees above average.

 

July's temperature range was only 27 degrees, from 66° to 93°.  This compares to an average range of 34 degrees (62° to 96°).  Only one other July has had a smaller range (2004's 24-degree range).

 

Although there were no heat waves, there was a streak of eight days with highs of 85° or warmer (July 22-29).  Finally, high dew points were a consistent feature of July as two-thirds of the days in July experienced dew points of 70° or warmer, giving the air an uncomfortable, tropical feel. 

 

Here are July recaps from previous years:

July 2022

July 2021

July 2020

July 2019

July 2018

July 2017

July 2016

July 2015

July 2014


July 2022 - Just The Second July With Highs of 80+ On Every Day

 


Clip art rays of sunshine

 

A typical July in New York has six days with highs cooler than 80°.  However, July 2022 had no such readings and joined July 1944 as the only other July in which every day had a high of 80° or warmer (it also happened in August 2015).  The coolest high was 81°, which occurred twice.  Overall, July 2022 was two degrees warmer than average (high/low of 87.3°/71.8°) and ranks as the 13th hottest July on record; it had the 8th warmest low, and tied for 16th warmest high.  

 

The number of days with highs of 85° or warmer was 25.  Only five other Julys have had more (in 2019, 2010, 1993, 1966, and 1944) and four others have had 25.  The hottest reading was 95°, which occurred on three days, and the warmest low was 79°.  Of the ten Julys with 25+ days of 85+, July 2022 had the fewest days of 87+ as it had 10 highs of 85° (7) and 86° (3).  

 

Chart - most july days with highs of 85 degrees plus

 

The coolest low was 65° on the Fourth of July.  Only five other Julys have had a chilliest low this mild or milder (the most recent was two years ago when the coolest low of 67° was the mildest coolest July reading on record).

 

During the first half of the month it appeared July's big story would be the very dry conditions as just 0.33" of rain was measured in Central Park through 7/15 - the least to fall in the first half of July since July 2002.  And while a large portion of the metro area continued to suffer through dry conditions in the second half of the month (Newark's July total was just 0.55", JFK's was 1.10"), 4.22" fell in Central Park, which was double the typical amount.  As a result, July's total rainfall ended up being very close to average (0.05" below).  Much of the rain fell from isolated strong thunderstorms. The most to fall on one day, 1.85" on 7/18, was a record for the date. 

 

A six-day heat wave, from 7/19-24, was the longest since the summer of 2013.  The average high/low was 94°/77°.  In addition to these six days, there were four other days with highs in the 90s (on 7/1 and 7/12-14); the total of 10 was three more than average.  The hottest day of the month occurred on the last day of the heat wave, with a high of 95°/79°.  Two other days during the heat wave, 7/20 and 7/23, had  highs/lows of 95°/78°.  (In addition to the large disparity in rain compared to Central Park, Newark also had a reecord-setting five-day streak of triple-digit highs).

 

Welcome to newark

 

Typically, June averages six lows in the 70s/80s and July averages 16.  This summer the respective numbers were one and twenty-four.  This increase of 23 days compared to June is the greatest increase from any June with 0, 1 , or 2 lows in the 70s.  Only July 2020 and 2010 have had more lows in the 70s/80s than July 2022 (tied with three other years that had 24 such lows).

 

Chart - lows of 70 june july

 

Finally, the 4.55" of rain that fell was the eighth time this amount was a monthly precipitation total.  The most recent occurrence was in April 2019, and there was another July with this amount in 1916. 

 

Here are July recaps from previous years:

July 2021

July 2020

July 2019

July 2018

July 2017

July 2016

July 2015

July 2014

 


Hot hot hot

  


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

 

Noahs ark in water

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.

 

So close_colbert
 Chart - july close to june

 

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".

 

Chart - greatest dif in precip btwn 2 mos

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.

 

July 2021
 

Here are other July recaps:

July 2020

July 2019

July 2018

July 2017

July 2016

July 2015

July 2014

 

 

 

 

 


July 2020 Is Seventh Hottest; Drought Eases Up

 

Seventh place

 

Following a June that was 2.3 degrees warmer than average, July 2020 was even more above average, +3.5 degrees, with an average high/low of 87.4°/72.6°.  The month's average temperature of 80.0° made it the seventh hottest July on record.  July records were set for mildest reading for coolest low temperature (67°) and the most lows in the 70s/80s (26).  Additionally, it joined eight other Julys with 14 or more highs of 90° or hotter.  Low temperatures were instrumental in placing the month so high in the rankings as it was third warmest in that category while the average high was ranked sixteenth.  Precipitation was also a significant story as the 6.58" that fell made this the wettest month of the year, so far, and the wettest of the 15 hottest Julys (July 2019 previously held that distinction).  Tropical storm Fay contributed a significant portion of the month's rainfall.

 

As mentioned above, July had 14 days with highs in the 90s, the most since 2010.  This included two five-day heat waves.  Despite the large number of hot days the heat wasn't overbearing as only one day had a high of 95° or hotter (96° on 7/6).  This was the fewest of any July among the 10 hottest.  However, there were nine days with lows of 75°+ (tied for fifth most of any July), including two in the 80s (the counterpart to high temperatures in the triple digits).  And of the six days with below average mean temperatures, just one of them had a low temperature that was cooler than average.

 

Highline during covid-19
.

After an exceedingly dry May and June, with both months reporting less than two inches of rain, July had 6.58", making it the wettest month so far this year (nearly double the combined rainfall of the preceding two months).  More than half of the rain was from tropical storm Fay on 7/10 (2.54") and a severe thunderstorm the evening of 7/22 that dumped 1.23" in an hour.  (Newark Airport, just 20 miles to the west, was much rainier, with 11.17" measured - its wettest July on record).

 

Chart - july 2020 top 10 julys

 

Finally, June and July 2020 were the seventh warmest June-July combination.  And the number of lows of 70°+ in June and July (37) tied June-July 2010 for the greatest number.  (37 is the  average number for an entire year.)

 

Chart - hottest june_july combos

 

Here are previous recaps of July from 2014 thru 2019:

July 2019

July 2018

July 2017

July 2016

July 2015

July 2014

  Tropical


 


A Look at New York City's Hottest Weekends of All Time

 

Waterskiing

 

On the one hand, if you work a Monday-Friday schedule and have access to a beach or pool, a hot weekend can be delightful.  On the other, if you don't have access to a body of water hot weather can be brutal, especially if you have outdoor plans or a wedding to attend.  This summer, the weekend of July 18-19 had highs/lows of 91°/72° and 94°/77°.  Hot, yes, but far from the most torrid weekends of all time in New York.  This analysis looks at conditions in two ways - by mean temperatures and by high temperatures.  In order to qualify, both Saturday and Sunday had to have highs in the 90s or hotter and lows in the 70s or warmer. 

 

Looking at mean temperature, the two hottest weekends were Aug. 13-14, 1988 (highs/lows of 96°/79° and 99°/80°) and Aug. 8-9, 1896 (95°/79°, 98°/82°).   Last summer (2019) had the third hottest weekend, with highs/lows on July 20-21 of 95°/82° on Saturday and 95°/80° on Sunday.  Focusing on high temperatures reveals that the five hottest weekends are different from the top-five based on mean temperature, with the hottest occurring on July 3-4, 1966 (highs of 100° and 103°), followed by July 20-21, 1991 (100° and 102°).  These are the only weekends in which both days saw highs in the triple digits; four other weekends had one day of 100°+.

 

Hot weekend

 

And here are a few other findings of note. 

  • The second earliest and latest scorching hot weekends occurred in the same year - 1895 (in the before-air conditioning era).  On June 1-2 the highs/lows were 96°/77° and 96°/76°; on Sept. 21-22 the highs/lows were 95°/77° and 95°/75°.   The earliest torrid weekend, in 1987, occurred two days earlier than 1895's, on 5/30 and 5/31 (with highs/lows of 97°/74° and 94°/76°).
  • Besides 1895, 1953 also had two sizzling weekends. The most consecutive summers with a hot weekend were in 1943, 1944 and 1945.

 

Chart - summer 1943 1944 1945

 

  • The weekend of July 20-21 has been very hot in three summers: 1957, 1991 and 2019.
  • Finally, the first weekend with lows in the 80s on both days occurred in 2019 (82° and 80°).  However, the weekend of July 23-24, 2011 had the warmest low of these select weekends - 83° on Saturday.

 

 Chart - 10 hottest mean temps in july

 

Chart - 10 hottest highs in july

 Scorching hot


Here are other heat-related posts:

Revisiting New York's Hottest Summers

"Super" Heat Waves (95°+)

Hot, Wet New York Summer

Low Temperatures of 70° or Warmer

The Heat is On: New York's "Hell Week"


Cooling Thunderstorms Prevented July 2019 From Ranking Among 10 Hottest Julys

 

Lightning strike nyc

 

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 3:00 PM 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.)

 

Chart - rainfall 15 hottest julys

  • 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.

 

Charts - 90s in july by decades

 

  • 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 with 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.

 

Cartoon devil

  • 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.

 

Chart - rainy may june july

  • 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

 

 


Lackluster Heat Waves

 

Lackluster

 

This post was inspired by the rather tepid four-day heat wave of Aug. 5-8, 2018, which had an average high of 90.8° (with highs of 91°, 92°, 90° and 90°).  Of the close to 70 four-day heat waves that have occurred since 1870 (thru June 2023) only one, in July 1896, had a lower average high, 90.3°.  (2018's low-grade heat wave matched one in August 2009 and would be matched again in June 2021.)  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°.)

 

Chart- most tepid 4-day heat waves

However, the story changes when low temperatures are included in the analysis.  For example, August 2018's heat wave had an average low of 75.0°, 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.)

 

Chart - coolest 4-day heat waves based on mean temp

 

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).  


July 2018 Weather Recap: Hot Temperatures, Followed by Torrents of Rain

 

Rain slicker

 

If July 2018 were a cocktail its ingredients would be one part heat, three parts rain.  After a hot start, with temperatures nine degrees above average during the month's first five days (average high/low was 92°/78°), the rest of July was seasonably warm, which moderated the month's average temperature to 1.1 degree above average.  As for the rain, after a dry start, with just 0.24" measured through July 11, the skies opened up and the rest of the month was very rainy, with 7.21" measured.  With 7.45" in total this was the rainiest month in more than four years, since April 2014, and the rainiest July in fourteen (and the fourteenth wettest July on record).

 

In late July there were seven days in a row (July 21-27) in which measurable rain fell.  This was the fourth streak of six days or more this year, joining 1989 as the only two years since 1900 with four streaks of six days or longer.  (Besides the persistent rain, dew points throughout this week-long period were in the uncomfortable 72°-74° range.)

 

Chart - 6+ Days of Rain in 2018

 

The seven-day streak with rain was the first since 2012, but this year's had considerably more rain (2.89" vs. 0.86").  The last streak of seven days or more with more rain was in May 2009, when 3.81" fell.

 

Downpours on 7/12 and 7/30 were confined to upper Manhattan; Central Park had 0.71" and 0.37", respectively, but my neighborhood, Greenwich Village, four miles south of the park, was dry.  And during the afternoon of 7/17 Manhattan was the bulls-eye for torrential rain from a severe thunderstorm, with 2.24" pouring down in little more than an hour.  Conversely, on 7/27 thunderstorms during late afternoon thru evening produced more than an inch of rain in most parts of the metro area (and 3-5" in parts of east-central NJ) but Central Park had only 0.25". 

 

July's rainfall in Central Park was considerably more than the three other reporting sites in the metro area:

 Chart - July 2018 Rainfall

Other July observations: 

  • Four of the first five days in July had highs in the 90s; the only one that didn't was the 4th of July, but its high of 86° was the warmest reading on this holiday in five years.  However, due to its very warm low of 77°, the mean temperature was the warmest since 2010.

 

Chart - 4th of July

 

  • Thirteen days in a row (July 8-20) had highs of 80° or warmer, the longest such streak since one of 19 days in August 2016.  (The record is 62 days in a row, set three years ago.)
  • What was most impressive about the hot beginning to July were the low temperatures, all  which were 76° or warmer.  This happens almost as infrequently as five-day streaks with highs of 95°+.
  • This was the ninth July in a row with no lows in the 50s, the longest such streak in the years since 1900.  Before 1980 more than half of Julys had at least one low in the 50s, but since 1980 that portion has fallen to 25%.
  • By July 25 the month had picked up more rain than the combined amount in May and June (6.80" vs 6.64").

 

Here are links to previous July recaps:

2017

2016

2015

2014

 


July 2017 Weather Recap: Somewhat "Ho-Hum"

 

4th of july fireworks

 

The month of July, temperature-wise, was close to average (+0.3 degree), with slightly below average rainfall (4.19", more than half which fell in the first week).  Thru 7/22 temperatures were 2.3 degrees above average, but the final nine days were four below average.  Five days had highs in the 90s, which was below the average of eight.  Four of these 90-degree days were consecutive, from 7/19 thru 7/22, making this the third heat wave of the year.  It was then immediately followed by five days in a row with highs in the 70s, the longest such streak in July since 2009.  7/20's high/low of 94/77 tied 6/13 as the hottest day of the year.  Finally, the month's rainfall highlight was on 7/7, when 1.78" fell, much of it pouring down during a two-hour deluge before lunchtime.  Here are a few other observations:

 

  • July 4th was the warmest in four years, but its high of 85° was two degrees cooler than Easter Sunday's.  However, it started off much warmer, with a low of 70° versus Easter's morning low of 59°.  (And it was 24 degrees warmer than Memorial Day.)
  • Although the average low for July was 1.0 degree above average, the average high was 0.4 degree below average.  This somewhat mirrored June, which had an average high that was 1.1 degree above average and a high that was right at the average.
  • July's rainfall could have been considerably more but strong thunderstorms on 7/17 and 7/21 stayed north and south of Manhattan, and a predicted nor'easter on 7/29 stayed too far south and east of the City.
  • This was the eighth July in a row with no lows in the 50s, continuing the longest such streak on record (for the month of July).
  • July 1940, 1954 and 1963 had more than twice as many 90-degree days than July 2017, but their average temperatures were slightly lower, due to their average low temperatures, which were three degrees cooler:

 

July 2017 temperatures

 

  • July Fun Fact: July 1937, 1938 and 1939 all had the same average temperature (76.6 degrees).  

 

Weather.beach.umbrella  

 

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Days of 95 Degrees+ and "Super" Heat Waves

 

Sweltering hot

 

The majority of days with highs of 90° or hotter in New York fall in the 90-92 range (56% to be exact).  And while the average number of 90-degree days each year is eighteen (including readings in the triple digits), the average number of readings that reach 95° or higher is just three (and about one out of every four years have had no highs that hot, the most recent being the summer of 2017).  The most in one year was sixteen, in 1955.  What follows are some more hot-Hot-HOT weather observations, best read in a well air-conditioned environment:  

  • Eleven years (since 1872) have had ten or more days with readings of 95°+, with the most recent being 2002, which had 13.
  • Although 1955 is the year with the most days with highs of 95° or hotter, it ranks 19th in total number of 90-degree days (with 25).  Incredibly, nearly two-thirds of its 90°+ days were 95°+ (the average is one-in-six).

 

1955 chevy

 

  • 1970 has the distinction of having the most 90-degree days, twenty-two, without any being 95° or hotter.  And not far behind are 1959, which had just one of twenty-seven days reaching 95/100+, and 1939, which had one of twenty-four.  The most consecutive years with no days of 95°+ is two, which has happened four times, most recently in 2003 and 2004.
  • The greatest concentration of years with with well above-average number of days with 95°+ readings was 1952-1955, when there were nine in 1952, twelve in 1953 and sixteen in 1955 (1954 had four, two of which were highs of 100°).

 

Nyc-heat-wave-1953

 

  • Although 1917 had only six days in the 90s/100s, the last four, on consecutive days, were sizzlers, with highs of 98°-100°-98°-98°. 
  • The earliest excessively hot days occurred on April 18, 1976 and April 17, 2002, both which had highs of 96°, and on May 19, 1962 when the temperature topped out at a blistering 99°.  On the late side, the high reached 99° twice on Sept. 11, in 1931 and in 1983; and on Sept. 23, 1895 the high was 97°.
  • The most consecutive days with highs of 95° or hotter ("super" heat waves) is eight, in 1944.  There has also been a streak of six days (in 1953) and seven that were five days in a row.  The last time we experienced a "super" heat wave of five days or longer was during the summer of 2002 (which is the only one among the eight lengthiest to have no highs in the triple digits).
  • The hottest temperature ever recorded in New York, 106° on July 9, 1936, came in the middle of a three-day super heat wave, with the day before having a high of 97° and the day after, 102°.

 

106

 

  • The hottest early "super" heat wave occurred in 1925 when highs of 99°-99°-98°-96° were experienced from June 4 to June 7.  The latest was in 1895 when there was a streak of three days from Sept. 21 to 23 (95°-95°-97°).
  • In 1944, which had thirty-seven 90-degree days, the first twenty-four were below 95°, but then 11 of the next 13 were 95° or hotter (concentrated in the four weeks between Aug. 4 and Sept 2).
  • Perhaps the most famous super heat wave was July 1977's, which coincided with New York's infamous blackout.  However, although the blackout began on the first day of a nine-day heat wave, the five days in a row with highs of 95+ began the day after power was restored: 98°-98°-97°-100°-102° (July 15-19).  And after a one-day respite on the 20th (high of 92°) the next day's high jumped to 104°.  
  • In less than six weeks in the summer of 1949 (July 3-Aug. 11) there were three three-day super heat waves: 99°-102°-95° (July 3-5); 97°-99°-95° (July 28-30); and 100°-98°-99° (Aug. 9-11).

 

Air condtioning

 

  • Finally, the hottest super heat wave of four days or more was in 1993 when the five days from July 7-11 averaged 99.8°, with highs of 98°-100°-101°-102°-97°.  Two years earlier there was another streak of five days in a row, from July 17-21: 96°-99°-96°-100°-102°.  Then after a one-day break, when the high "cooled" to the upper 80s, the high on 7/23 was 99°.   (A three-day "super" heat wave on July 1-3, 1966 had an average high of 100.3°.)

 

Excessive heat warning

 

 95+

 Summer beach scene in coney island

 Super Heat Waves

 

Super

   
(I owe a debt of gratitude to Eugene DeMarco, a follower of NYC Weather Archive, whose spreadsheet showing the 90-degree days of every year, made this analysis so much easier for me to do.)

 

 

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