Philadelphia receives around 1,120 mm (about 44 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 Schuylkill and Delaware rivers running through the city have a documented history of flooding during periods of sustained heavy rain, and remnants of tropical systems moving up the East Coast occasionally add significant rainfall on top of routine weather. Summer convective storms can be intense, bringing damaging wind and hail. 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 KDIX (Philadelphia/Mount Holly, NJ) covers the region.
Learn more: How Does Rain Radar Work? · Open the full Rain Map