Historical weather data, all-time temperature records, and monthly climate averages for Radnor, PA. Explore typical weather conditions by week for trip planning, and see how today compares to the historical record.
April 5 in Radnor splits the difference between spring hope and lingering winter — average highs of 60° sound pleasant, but the record low of 22° set in 2001 is a reminder that frost isn't fully off the table. There's nearly a coin-flip chance (45%) of rain today historically, so keep an umbrella handy.
Radnor has seen the full extremes of Mid-Atlantic weather, from a brutal 108° in July 2011 to a bone-chilling -12° in January 1982 — a 120-degree swing between its worst moments. A single October day in 2010 dropped 7 inches of rain, and a February 2006 storm buried the area under 18 inches of snow.
Summer is peak Radnor, with highs topping out around 88-89° in mid-July, while mid-January is the time to stay indoors with average highs barely reaching 39°. If you're trying to dodge rain, avoid late July through early August — that stretch averages over an inch of precipitation per week.