Washington, D.C. receives around 1,050 mm (about 41 inches) of rain a year, fairly evenly spread across the seasons, with both winter nor’easters and summer thunderstorms contributing meaningfully to the total. The Potomac River and its tributaries running through the capital have a documented flood history, and the city’s historic Georgetown waterfront and low-lying areas near the National Mall have flooded during major storms in the past. Summer convective storms can be intense, occasionally bringing damaging wind alongside heavy rain that overwhelms the city’s aging drainage system. Because both slow river flooding and fast summer storms matter here, radar is most useful for tracking the faster-developing local cells. NWS Doppler radar KLWX (Sterling, VA) covers the region.
Learn more: How Does Rain Radar Work? · Open the full Rain Map