Philadelphia got a brisk wake-up call Monday, with temperatures at Philadelphia International Airport hovering near 39°F around 5:40 a.m. EDT on April 20, 2026. The day will stay on the cool side, partly to mostly sunny, with just a slight shot at light showers late in the morning and an afternoon high near 52°F before the real chill settles in tonight.
Freeze Warning Tonight
A Freeze Warning is in effect from 12:00 a.m. EDT Tuesday, April 21, 2026 through 9:00 a.m. EDT Tuesday for Philadelphia County. Overnight lows are expected to drop into the upper 20s to low 30s, with some spots possibly dipping to around 27°F. That kind of cold can be bad news for early blooms, tender plants and any unprotected outdoor plumbing. Residents are urged to protect vulnerable vegetation and cover or drain outdoor faucets, according to the National Weather Service Mount Holly.
What To Expect Today
Northwest winds will kick up this afternoon around 5 to 15 mph, with occasional gusts near 20 mph that will make it feel even chillier. There is a slight chance of a few light showers between about 9 a.m. and 2 p.m., but most commutes should stay dry. Skies clear out tonight, which will help temperatures tumble quickly, so bring in potted plants and consider letting an indoor-protected faucet drip if you are worried about exposed pipes.
Warm-Up Later This Week
After the freeze, a gradual warm-up moves in. Tuesday is expected to be sunny with a high near 58°F. By Wednesday and Thursday, temperatures climb into the upper 60s to low 70s, with a possible high near 73°F on Thursday. A front may slide through later in the week, bringing an increasing chance of showers over the weekend, so it is smart to keep outdoor plans a bit flexible.
Sign Up For Alerts
City residents who want official emergency and weather notifications can sign up for ReadyPhiladelphia to get texts or emails from the Office of Emergency Management. The system offers multilingual alerts and provides quick updates on any changes to warnings overnight. Visit ReadyPhiladelphia for details. Gardeners should move vulnerable potted plants indoors and cover outdoor beds before midnight.
