Washington is waking Friday with lower-70s dewpoints, and afternoon temperatures are expected to reach the 80s. A north wind behind a passing cold front will make the afternoon feel a little less summerlike, even as the thermometer stays in the 80s.
Friday Stays Mostly Dry Before A Cooler Saturday
Friday afternoon should turn partly sunny, with north winds of 5 to 8 mph and only a small chance of rain. Friday night will see another push of cooler air.
Saturday looks like the weekend’s best outdoor window, though it will be noticeably cooler with partly sunny skies and a high near 79. Northeast winds around 7 mph will keep conditions comfortable, while Saturday night stays mostly cloudy with a low around 67.
Sunday Brings The Weekend’s Storm Risk
Sunday starts partly sunny and warmer, with a high near 83, and showers and thunderstorms are possible Sunday afternoon.
Showers and a few thunderstorms Sunday afternoon may continue overnight. Outdoor plans may still work earlier in the day, but umbrellas and a flexible schedule will become more useful by evening.
Rain Chances Continue As Temperatures Slide
Monday brings another chance of showers, with a high in the 70s. Rain chances continue next week as temperatures cool.
The unsettled pattern may linger through the middle of next week. Temperatures are expected to be in the upper 50s to 60s by midweek, with showers possible.
How This Forecast Fits the Broader Climate Picture
According to the National Weather Service Baltimore/Washington, Washington’s normal high for Sept. 18 is 80 degrees, providing a baseline for the forecast’s cooler Saturday and the warmer conditions expected Friday and Sunday. NOAA says its official climate normals are calculated over a uniform 30-year period, so that comparison describes typical conditions rather than establishing a long-term climate trend from this week’s forecast. The Fifth National Climate Assessment reports that average annual precipitation in the central and eastern United States was 5%–15% higher in 2002–2021 than in 1901–1960, a long-term regional trend attributed to climate change that does not determine this week’s weather. The D.C. Department of Energy and Environment also distinguishes stormwater or interior flooding caused by heavy rain and overwhelmed drainage systems from flooding shown on conventional river and coastal floodplain maps; a rainy forecast alone does not establish that flooding will occur.
The forecast calls for increasingly damp and cool conditions after the weekend. For Friday and Saturday, lighter winds and limited rain offer the clearest opportunity for outdoor plans before the wetter stretch takes over.
