D.C.’s Late August Heat Waves

 

Sunrise from Charles Co., Maryland  (Photo Credit: Kristen Leitch)

Today will be the seventh day of D.C.’s current heat wave.  A “heat wave” is defined as a minimum of three consecutive days with highs in the 90s.  Although August is the second hottest month of the year in the Nation’s Capital, it gets harder to sustain the hot weather as the month wears on due to the decreasing sun angle and length of daylight.  Average daily high temperatures in Washington, D.C. fall from 89° as recently as August 11 to 86° less than three weeks later on August 27.  Nevertheless, there have been some memorable heat waves in the D.C. Metro Area this time of year in recent decades.

2022: Today is well-positioned to be the hottest day of D.C.’s current heat wave with highs approaching the mid-90s.  This the second longest heat wave of the summer behind an eight-day stretch from July 18 to July 25.  It is also D.C.’s longest heat wave to occur during the final 10 days of August since 1993.

2018: This was one of the rare instances that August was warmer than July in the Nation’s Capital with an average monthly temperature of 81.0° (combining daily high and low temperatures), compared to 80.7° in July 2018.  Appropriately, the month concluded with a five-day heat wave from August 27 – August 31.  The hottest day occurred on August 29 with a high/low of 94°/79° at National Airport.

2016:  Although not during the final third of the month, August 2016 was the last time Washingtonians experienced triple-digit heat, from August 13 – August 15.  August 2016 finished 0.1° behind August 1980 for D.C.’s hottest on record.

1998: High temperatures in the Nation’s Capital were in the 90s on all but one day from August 22 – August 31.  A record-tying high of 97° occurred on August 25.  The final 10 days helped catapult August 1998 to being D.C.’s hottest month of the year.  It would remain D.C.’s hottest August until 2002 when it was 100° twice and 99° twice.

1993: The 1993 summer was a hot one in the Nation’s Capital with multiple record highs.  Although some have since been broken, that doesn’t diminish the intensity of D.C.’s 1993 summer heat.  The final seven days of August 1993 saw the start of a 10-day heat wave that continued into September.  The hottest day was August 26 with a high and low temperature of 96°/77°.