Feeling Like Fall ?

Following DC’s third warmest July and a warm start to August, there has been a discernable change in the weather over the last few days.  By the third week of August, average temperatures have fallen from their peak in mid-July.  DC’s hottest average daily high/low temperatures are 89°/71° for much of July, but are down to 86°/70° today.

The last few days have felt more like September than mid-August.  That’s because three of the last four days have been cooler than average.  You have to go back to mid-June to find a stretch of three or more consecutive days of cooler than average weather.  In fact, from July 1 – August 15 the Nation’s Capital had a total of only two cooler than average days. 

It has also been a wet August so far.  This morning’s rain makes today DC’s twelfth day with measurable rainfall since August 1.  While 6.22” of rain has occurred as of yesterday, DC would need at least 8.92” for August 2020 to rank among the 10 wettest on record.

Temperatures for this August in the Nation’s Capital are 1.2° warmer than average through August 18.  That’s cooler than it was for the same period last year.  DC had 11 days in the 90s between August 1 – August 18, 2019, while there have been only four such days so far this month.  While high temperatures haven’t been as extreme so far this August as compared to last year, overnight low temperatures have largely been warmer than average.  That’s an important factor to consider as above average daily low temperatures go a long way toward boosting average monthly temperatures.

Washingtonians recently set a record for longest consecutive stretch of days that temperatures remained at or above 70° from June 27 – August 15.  June 2020 was 1.8° warmer than average and last month was 4.1° warmer than average in the Nation’s Capital.  Nevertheless, there haven’t been any record highs or days with triple-digit heat. 

By the second-half of August the gradual shift toward fall is underway.  The sun sets at 7:56 PM today, compared to 8:37 PM on June 21.  Although mid-to-late August gradually sees decreasing average temperatures and a slow reduction in the amount of sunlight, it can still get quite hot this time of the year.  Such was the case during recent heat waves in the Nation’s Capital that spanned from August 27 – August 31, 2018 and August 17 – August 22, 2019.  In fact, DC’s high and low temperatures one year ago today were 98°/78°.  That tied not only DC’s record high for August 19, but also tied the daily record high-low temperature.

While no record-challenging heat is expected during the next 7 – 10 days in the DC Metro Area, NOAA’s Climate Prediction Center expects warmer than average temperatures for that time period.  Average high temperatures in the Nation’s Capital fall to 84° by August 31.