89.6°FJuly average high at Reagan National
Summer is the long season
At Reagan National Airport, DC's official weather station, July averages a high of 89.6°F, and NOAA's normals show cooling demand in every month from May through September. If your phones get busiest in summer, those five months are when a missed call costs the most.
Source: NOAA NCEI, U.S. Climate Normals 1991-2020, Washington Reagan National Airport.