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

June 2020: Warm & Dry

 

June's temperatures rebounded after a chilly April and May (2.7 and 2.1 degrees below average, respectively).  At 2.3 degrees above average, it was the warmest June in 10 years (and 16th warmest overall).  Fourteen days were five degrees or more above average.  Besides being warmer than average, June was also on the dry side, with the least rainfall in 21 years (and 22nd driest overall).  The month had 1.76" of rain, which was very similar to May's 1.65" (like June, May was the 22nd driest).  This was just the sixth time (since 1869) that May and June both received less than two inches, and the first time that consecutive months had less than two inches of precipitation since April and May 2016 .  

 

Based on average temperature, June had the biggest warm-up following May since 2008.  And out of all of the years of measurement, it was the 12th biggest warm-up after May (tied with two other years).

 

Although the number of days of 80°+ was close to average (18, including the final twelve days of the month), it was well above average for days of 85°+.  13 days had highs of 85° or warmer, with 11 of them between 85° and 89°.  The two other days had highs of 90° (on June 22 and 28).  At one point there was a streak of seven days in a row with highs of 85°+, the longest streak in June since 2010.  Furthermore, the month's 11 days with lows in the 70s was more than double the average for June.  Only three other Junes have had more lows of 70°+ (2010, 2005, and 1943 had 12; June 1895 had the same number as June 2020).

Through 6/26 it appeared the month would easily be among the ten driest Junes as just 0.98" had fallen.  Beginning 6/12 there were 15 days in a row with no measurable rainfall (the longest dry streak since the fall of 2017, which had a streak of 18 days).  Then 0.78" fell in the next three days.  The 0.58" that fell on 6/29 (in less than an hour) made it the rainiest day of June (and a wind gust of 47 mph was the highest of the month). 

 

Finally, the first half of 2020 was the driest since 1995 (16.15" was measured in Central Park, eight inches below average), and among all years it was the 17th driest first half of any year (tied with 1957).

 

 

Below are links for previous June recaps:

2019

2018

2017

2016

 

 

 

 

 

 

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 degrees 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 based on mean temperature 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 2021). 

 

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 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, in 2016, 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.

 

 

 

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 close to 70 four-day heat waves that have occurred since 1870 (thru June 2021) only one, in July 1896, had a lower average high, 90.3 degrees.  (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°.)

 

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).  

June 2018 Weather Recap for New York

 

Following an April that was significantly colder than average, by 3.6 degrees, and a May that was 4.5 degrees milder than average, June was "just right" as it was close to average, 0.2 degrees above average.  This was the closest to average for any month since June 2015 (0.2 below average).  However, despite the month being average overall, the first half was cooler (and drier) than average while the second half was warmer (five days had highs of 88° or hotter) and wetter (relative to the first half, since the amount that fell was average).  Here are a few other observations of interest: 

 

• Father's Day had a high of 91°, which was 37 degrees hotter than Mother's Day (typical difference between the two holidays is thirteen degrees).  It joined Father's Day 2010 as having the greatest difference in high temperature from Mother's Day (going back to 1960).  Also, this was the first Father's Day with a high in the 90s in twelve years (and the seventh since 1960).

• The hottest day of the first half of the year occurred on the last day of the period as the high reached 93° on 6/30. (The second half of the year began with a high of 96° on 7/1).

• Rainfall was below average, 3.11" vs. a norm of 4.41".  Three-fourths of this amount fell in the last two weeks of the month.  And much of it, 1.36", fell on 6/28, highlighted by the downpour during the evening rush hour, which saw 0.93" pour down in about an hour.  This storm brought to mind the severe thunderstorm of 5/15 that snarled rush hour traffic.  However, despite producing less rain (0.58") it was characterized by destructive winds that killed five people who were struck by falling trees.

• June was the closest to average a month has been since June 2015, which was 0.2 degrees below average.  Of the twelve months that have been 0.2 degrees or closer to average since 2000, five of them have been in June.

 

 

 

 

 

Comparing High Temperatures on Mother's Day and Father's Day

 

Since Father's Day is about five weeks later than Mother's Day its high temperature is, on average, about thirteen degrees warmer (82° vs. 69°).  However, in 2018 there was a huge disparity in the temperatures as Father's Day had a sizzling high of 91° while Mother's Day's was only 54°.  This 37-degree difference tied 2010 for the greatest difference in temperature between the two holidays (and there was a 36-degree difference in 1994).  However, not every Father's Day has been warmer.  Since 1960 there have been eight Mother's Days with warmer highs (most recently in 2014), with the greatest difference being 28 degrees in 1970.  And sometimes the two holidays have similar readings; for example, in 2000 and 1974 they had the same high temperature.

 

 

 

June 2017 Weather Recap: A Cool & Dry Start, Followed by Warm & Wet Second Half

June 2017 was close to average temperature-wise (+0.6 degrees) and rainfall was close to average as well (4.76" vs. average of 4.41"), but as so often happens with averages, they masked the true "personality" of the month.  Specifically, the first nine days were six degrees cooler than average, and then the rest of the month was three degrees warmer than average; meanwhile, after less than half an inch of rain fell thru June 16, the remaining two weeks were on the rainy side, with more than four inches measured.

 

The highlights of the month occurred mostly during two eight-day periods.  The first, from June 6-13, pertained to temperature, with two days that were 10 degrees or more below average (highs in the 50s and 60s) quickly followed by three that were 10+ degrees above average (highs in the 90s).  The month's coolest and hottest days (based on daily mean temperature) were at the beginning and end of this eight-day period: a high/low of 58/52 on 6/6 (fourteen degrees below average) and 94/77 on 6/13 (fifteen degrees above average).  The second eight-day period was rain-related, most of which fell during three downpours of an inch or more on 6/17, 6/19 and 6/24; these periods of heavy rain each lasted two to three hours.   

 

Some additional observations:

• The month's average high of 79.3° was right at the average, but the average low was 1.1 degree warmer than average.  This was largely due to ten days having lows of 70° or warmer, double the typical number - only four other years have had more.

 

 

• After three days in a row of 90-degree temperatures in May (5/17-19), the next twenty days saw no highs of 80° or warmer.  In fact, the first 80-degree day in June, on 6/9,  was the deepest into June with no 80-degree days since 2003, when it happened on 6/10.

• Five days in a row had measurable rain from 6/2-6, but only 0.19" was measured, the smallest amount to fall during five consecutive days since March 1982.

 

 

• On average there are four or five days with highs of 88° or 89° before the sixth day in the 90s occurs, but this year there were no such days - the first time this has happened since 1995.  By contrast, last year had seven such days before the sixth high in the 90s occurred, 2015 had twelve, and 2014 had eight.

• Four days in a row, 6/20-23, had a high of 83°.  Then, after a high of 84° on 6/24, there was another high of 83° on 6/25.

• Father's Day (6/18) and Gay Pride Day (6/25) had similar conditions, with partly cloudy skies and highs/lows of 85/70 and 83/68, respectively.

 

Here are links to previous June recaps:

June 2016

June 2014

June 2013

 

 

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Days of 95 Degrees+ and "Super" Heat Waves

 

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).

 

 

• 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°).

 

 

• 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°.

 

 

• 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).

 

 

• 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°.)

 

 

 

 

 

 

   
(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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The Towering Clouds & Beautiful Sunsets During Summer 2016

 

I've always had an appreciation for clouds and sunsets.  Five years ago I probably wouldn't have been able to write this post because I didn't have my smartphone with its camera.  Now I'm able to snap photos at a moments notice, enabling me to capture this summer's overabundance of photo-ready thunderheads and stunning sunsets.  And because I live in the West Village I probably notice them more since the low-rise buildings make the sky much more accessible than in Midtown Manhattan.  I hope you enjoy the photo revue that follows ... 

 

 

The photo display begins with one of me along the Westside Highway at dusk during Memorial Day weekend.

 

Rays of the setting sun stream over Sheridan Square in Greenwich Village.

 

I took this photo during a June visit to Pittsburgh to see my mother. These clouds brought to mind those I'd often see over the Atlantic Ocean close to sundown on Fire Island.

 

Taken on July 1, this photo shows a thundercloud from a storm that struck half an hour earlier. Although it was around 9PM the top of the cloud was catching the rays of sun that was below the horizon.

 

Early evening sun filtered through a slate gray sky over Sheridan Square.

 

This isn't a cloud formation in New York but it deserves an honorable mention.  I snapped the photo of this breathtaking thunderhead during a weekend visit to south central Pennsylvania in the midst of a late July heat wave.

 

Taken from my kitchen looking east as the full moon was rising.

 

This was the view on 7/28 looking east from the 44th floor of an apartment building on the  Upper West Side. The light pastel coloring was the result of a fire in a warehouse in Long Island City (Queens) an hour earlier.

 

Taken as I was walking to the subway after work on 42nd St. across from across from Grand Central Terminal.

 

Looking west from Sheridan Square at around 6PM in mid-August. Seeing it I felt I was in the presence of the Divine.

 

Early evening on a hot day in mid-August.  These mountainous clouds brought a quick downpour to upper Manhattan, but not to Greenwich Village.

 

Similar view and thunderclouds as the previous photo but on a different day one month later.

 

The same cloud formation as it moved behind the apartment building at 10 Charles St.

 

Wispy and puffy clouds over the West Village.

 

Sunset on the Saturday of Labor Day weekend, taken on Christopher St. pier, which looks out across the Hudson River.

 

This is how the sun's rays from the above sunset reflected on the bank of towering clouds in the east.  Reminds me of rainbow sherbet.

 

I snapped this photo shortly after I came out of the Christopher St. subway station in the early evening. This view is looking east.

 

Taken the evening of Sept. 11 as I left the gym on Seventh Ave. South.

 

Taken on Sept. 14 close to the West Side Highway in Chelsea, shortly after a late afternoon thunderstorm. A few hours earlier the temperature was in the low 90s, the last 90-degree day of the year.

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6PM on Sept. 15, awaiting take-off at LaGuardia Airport.

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Finally, a golden sunset on Sept. 17 during a visit to my childhood neighborhood in McKees Rocks, PA.

 

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