Revisiting New York's Hottest Summers

 

Although summer officially falls between June 21 and September 21 (give or take a day, depending on the year), for the purposes of this analysis the meteorological definition of summer is used, which is June 1 thru August 31.

 

 

 

• New York's five hottest summers (since 1869) have all occurred since 1960: 2010, 1966, 1993, 1983 and 1999.  The fact that just one of the years is from this century may surprise some since these years were so warm worldwide.  

• The summer of 1966, New York's second hottest on record, has the honor of having the hottest average monthly high temperature.  Although July 1999 was the hottest month on record based on mean daily temperature (average of the day's high and low), the average high in July 1966 was hotter than July 1999 by 0.1 degree, 90.3° vs 90.2°.  However, July 1999's average low was 3.5 degrees warmer (72.6° vs 69.1°) and that's what easily put it on top.      

• Although 1991 and 1993 had the most 90-degree days for a calendar year, each with 39, 1993 had the most during the summertime period.  It had 35, followed by 1966 with 34 and 2010 with 32.  1991 had 31, ranking fourth.

 

 

• July 2010 missed tying July 1999 as NYC's hottest month on record because of a 0.1 degree difference in average high temperature.  However, 2010's consolation was that it become New York's hottest summer on record because June and August were hotter.  

• Eight Julys have had a a mean temperature of 80.0° or higher (the most recent was in 2020).  The first time it happened was in 1952.  (July 2011 and 2010 are the only back-to-back Julys with mean temperatures above 80.0°.)  A monthly temperature this warm also occurred once in August, back in 1980. 

• Two of New York's five hottest summers were also extremely dry.  1966 had the the driest summer on record, with every month receiving less than two inches of rain (1.17" in June; 1.25" in July and 1.89" in August).  The summer of 1999 was the fourth driest and featured the second driest June (0.59") and the driest July on record (0.44").  The combined rainfall of those two months was barely more than one inch (average rainfall in June and July is close to eight-and-a-half inches).
  

 

Other posts about summertime:

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

Unbearably Warm Summer Nights

Ranking Hot New York Summer by Concentration of 90-Degree Days

New York's Hottest Weekends

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Comments

[William]

hi Rob. how confident are you about this summer being torrid? 2010, 2002, 1995, 1988 and 1980 all had 29 or more 90° days. based on this seven to eight year pattern, I predict this year will be no different.

[Rob]

An interesting observation, but I don't think weather patterns adhere to numerical patterns. And during the 30-year period you cited, there were also other hot summers: 1983, 1988, 1991, 1993, 1999 and 2016. Bottom line, I think it's a crap shoot.

[William]

Well, I guess my prediction was wrong. New York didn't quite reach (29) 90° days in 2018, but the city did get close though, with 25, including four days with a high of 89°.

[Harry Mandel]

One thing I noticed, I think purely coincidental, is most of the "same digit" years in the 20th century had very hot summers, I know that is true of 1911, 1944, 1955, 1966, 1977, 1988 and 1999; not as sure about 1922 and 1933. I believe 2011 was pretty hot too.

[William]

Neither 1922 nor 1933 had an exceptionally hot summer, as each year had ten and 21 ninety degree days respectively.

[Elaine]

Just happened upon your blog, and am enjoying it. Have forwarded your story on NYC’s hottest summers to a friend in Denmark, where they only began to know real summer heat in 1997, which was also a drought year there. I’m fluent in Danish, and often Google current and historical weather stats from there and from Greenland, where I lived from 1981 through 1986, before global warming became apparent.

The winters of 1982-83 and 1983-84 were the second and third coldest winters in Greenland’s recorded history, topped only by 1882-83. When I was there in 1982-83 and 1983-84, there was serious speculation at the governmental level regarding whether Greenland might be entering “a mini second ice age.” In the 1982-83 winter, the usually ice-free harbor of the capital, Nuuk/Godthaab, was frozen nearly a kilometer from shore, so that supply ships had to have their goods unloaded and transported via snowmobile. And in 1983, it snowed every single month, including July (3-4”), something not even the elders had ever experienced.

Little could we imagine that the ice cap could be melting, nor that the entire west coast would be ice-free year round! In July 2018, a couple I know there set sail from Nuuk, crossing the Davis Strait and Hudson Bay, and managed to navigate all the way through the Northwest Passage (!) to the Pacific Ocean, then circumnavigated the globe, returning to Greenland by summer 2019 (fortunately just before the pandemic would have made such travels nearly impossible). This summer, they sailed southward from Nuuk, around Cap Farvel, and up the east coast of Greenland, which used to be very inaccessible due to pack ice. They are now on their way back to Nuuk.