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.