Weather in Philadelphia in April

A good month. April works. It is not the peak, but nothing about it fights you. Highs average 17.1 °C, lows 5 °C, and rain falls on 11 days — nothing in the month is working against you.

April ranks 5 of 12 in Philadelphia: past the worst of the year but short of September, which is the month to book if the dates are open.

Rain on 11 days, 3 of them heavy. Enough to need a plan B, not enough to need a plan around it. Pack for 17.1 °C days and 5 °C nights; the spread matters more here than any single number.

What the averages hide

Averages flatten a month, and this one hides a few things: 3 nights fall below freezing. Across the twenty years measured, the hottest April day reached 33.8 °C and the coldest night fell to -4.8 °C, and the wettest single day dropped 92 mm — roughly 95% of the month's rain in one day.

April is statistically steady but not small: the year-to-year variation is modest in relative terms, yet the wettest April on record still delivered 221 mm against 47 mm in the driest. In a month this wet, even a tame spread is a lot of rain in absolute terms — the 97 mm average is a reasonable planning figure, not a promise.

Wind is light at 8.2 km/h, so the temperature on the page is close to the temperature on your skin, and humidity runs at 78%, high enough to notice on the warm days without dominating them.

How April sits in the year

The month is on the way up: 6.8 °C warmer than March, and May adds another 5.2 °C. Late in the month feels noticeably different from the start of it, which is worth knowing if the trip is short.

Daylight in April

13.2 hours of daylight, gaining 1.2 hours across the month. That is between Philadelphia's extremes of 15 and 9.4 hours, so days are long enough not to constrain the plan.

An inland climate

With no coast nearby, the year swings a fair way — 34.9 °C between the warmest afternoons and the coldest nights, wider than any coastal city at this latitude would manage.

How busy it gets

Busy. Popular without being frantic; book the things you care about, improvise the rest.

Crowd levels are estimated from climate desirability and school-holiday calendars, not from visitor numbers.

April in Philadelphia versus nearby

If Philadelphia is one option among several, the nearby comparison is worth making. New York City is the weaker option in April — 5.1 °C cooler, the same number of rain days. Washington is close enough to be a coin toss — within a degree on temperature, 1 day less rain.

So: April works, with September the better month by 12 points if the dates can move. If they cannot, nothing here should stop you booking.

Every month in Philadelphia

See all twelve months in Philadelphia, or where else to go in April.