A Wet Month Comes to a Close

 

August 2021 will finish as a warmer and significantly wetter than average month in Washington, D.C. That’s despite a cool and almost fall-like start to the month.  In fact, temperatures on six of the first seven days of August were cooler than average.  Washingtonians didn’t see the first 90° August day until August 6. 

This month’s weather has been streaky.  Following the cool start, Washingtonians had a 7-day heat wave from August 8 – August 14.  The tail end of that heat wave coincided with the start of a stretch of nine consecutive days with measurable rainfall from August 13 – August 21.  During those nine days, a total of 6.92” of rain accumulated at National Airport.  Most of that rainfall occurred on two days when a combined total of 4.66” fell on August 14 and August 20.

This rainy stretch of weather helped prevent daily high temperatures from soaring as evidenced by only three days in the 90s during the nine-day period.  Washingtonians know triple-digit heat can occur at any point during the month.  But the frequent clouds and rainfall have prevented any such weather this month.

Showers and thunderstorms have been an almost daily occurrence in the D.C Metro Area this month.  The nature of summertime showers and thunderstorms is for them to often be spotty and localized.  That means while some areas can see appreciable rainfall, others not far away see little or no rain.  For example, through August 30, National Airport had 9.07” of rain.  Meanwhile, Dulles Airport had only 4.91”.  However, Dulles Airport will also finish with a wetter than average August for a fifth consecutive year.  Average monthly temperatures at Dulles Airport will also finish warmer than average for a fourth consecutive year. 

The average monthly temperature at National Airport (combining daily high/low temperatures) will finish more than 1° above average.  August 2021 will be D.C.’s fourth consecutive warmer than average August.  The hottest temperature in the Nation’s Capital this August was 96° that occurred on three consecutive days (August 11 – 13).  Meanwhile the coolest day this month was August 7 with a high/low temperature of 77°/69°.

Wettest August’s in Washington, D.C.  (Source: National Weather Service)

1.  14.41” (1928)
2.  14.36” (1906)
3.  14.31” (1955)
4.  12.93” (1875)
5.  9.91” (1933)
6.  9.75” (1905)
7.  9.49” (1942)
8.  9.17” (1967)
9.  9.07” (2021)
10.  9.00” (1948)