So far, the month of August has been slightly cooler than normal. There have only been two days this month with above-average temperatures. Now, let me set the record straight: It hasn't been abnormally cold so far this month, but it will definitely be much cooler than normal over the next two days.
- (Forecast morning lows Friday)
Low temperatures Friday morning and Saturday morning may drop into the 50s at Reagan National Airport. This hasn't happened in 10 years, since August 7th, 2004, when the mercury dropped to 58 degrees. Since 2009, temperatures haven't dropped into the 50s at Reagan National until September 1st, the 11th twice, the 14th and the 15th, so we're nearly a month ahead of where we've been over the past few years.
The average low doesn't eclipse the 50s until September 24th. Looking back a little further into the climate data, temperatures in the 50s in the month of August have been largely absent in D.C. after 2004.
There were numerous times prior to that date though, as Reagan National reached the 50s in August in 2000, 1998, and 1997, four times in 1994, once in 1992 and two times in 1989. That gives 12 occasions in the past 25 years, though none in the past 10. I guess we'll see if we can break the warm streak starting tonight.
- (Secondary cold front will move through this evening)
The forecast low tonight for D.C. is 60 degrees. As a secondary frontal boundary pushes through the region this afternoon and evening, drier air will settle overhead along with clearing skies overnight. By the early morning, clear skies and light winds should lead to plenty of radiational cooling, which may help D.C. reach its potential. The wild card: The Potomac's water temperature still stands at 77.5 degrees. A slight shift in the wind could keep the temperature from dropping below 60.