Patchy Fog Low: 57 °F Wednesday Patchy Fog then Sunny High: 83 °F Wednesday Night Mostly Clear Low: 54 °F Thursday Mostly Sunny High: 77 °F Thursday Night Mostly Cloudy Low: 60 °F Friday. Downingtown, PA Hourly Weather | AccuWeather 7 PM 53° RealFeel® 47° 51% Showers Wind WSW 8 mph Air Quality Fair Wind Gusts 12 mph Humidity 67% Indoor Humidity 39% (Ideal Humidity) Dew Point 42° F. Find the most current and reliable hourly weather forecasts, storm alerts, reports and information for Downingtown, PA, US with The Weather Network.