Climate averages 1991–2020
Philadelphia weather
in May.
A warm, wet month: the 5th warmest and the 4th driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
May is a warm month in Philadelphia: daytime highs average 22.4°C and nights cool to about 12.3°C. By daytime temperature it is the 5th warmest of the 12 months.
Expect about 90 mm of rain on roughly 11 days, which makes May a wet month (the 4th driest of the 12 months). Daylight, from sunrise to sunset, lasts about 14 h 22 min on an average May day.
The nearest other city in this atlas is Camden (5 km away). In May its highs average 22.3°C, about as warm as Philadelphia, with 86 mm of rain.
Among the 498 cities listed in the United States, Philadelphia ranks joint 281st of 498 for the warmest May highs and joint 293rd of 498 for the driest May (rainfall, lowest first). The mean May high of those 498 cities is 23.8°C; Philadelphia is 1.4°C cooler than that mean.
From May to June, average highs rise by 4.8°C to 27.3°C, and monthly rainfall rises from 90 mm to 97 mm.
The annual picture
May in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Philadelphia climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 4.5°C-3.3°C | -3.3°C | 82 | 9.3 | 9.710 h |
| February | 6.2°C-2.8°C | -2.8°C | 76 | 9.0 | 10.711 h |
| March | 10.7°C1.0°C | 1.0°C | 104 | 10.5 | 11.912 h |
| April | 17.2°C6.7°C | 6.7°C | 92 | 10.2 | 13.213 h |
| May, selected | 22.4°C12.3°C | 12.3°C | 90 | 11.1 | 14.414 h |
| June | 27.3°C17.6°C | 17.6°C | 97 | 10.6 | 15.015 h |
| July | 29.9°C20.7°C | 20.7°C | 98 | 10.7 | 14.715 h |
| August | 28.8°C19.9°C | 19.9°C | 95 | 10.2 | 13.714 h |
| September | 25.1°C16.3°C | 16.3°C | 104 | 9.2 | 12.512 h |
| October | 18.6°C10.0°C | 10.0°C | 91 | 8.1 | 11.211 h |
| November | 12.4°C4.2°C | 4.2°C | 74 | 7.8 | 10.010 h |
| December | 7.0°C-0.4°C | -0.4°C | 100 | 9.3 | 9.49 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
May in nearby cities
- Camden in MayUnited States · 5 kmHigh 22.3°C · Low 12.2°C · 86 mm rain
- Cherry Hill in MayUnited States · 11 kmHigh 22.1°C · Low 12.3°C · 86 mm rain
- Wilmington (Delaware), United States in MayUnited States · 40 kmHigh 22.0°C · Low 12.4°C · 89 mm rain
- Trenton in MayUnited States · 46 kmHigh 21.8°C · Low 11.6°C · 88 mm rain
- Bethlehem, United States in MayUnited States · 77 kmHigh 21.2°C · Low 10.3°C · 93 mm rain
- Reading, United States in MayUnited States · 78 kmHigh 22.0°C · Low 11.5°C · 92 mm rain
- Allentown in MayUnited States · 78 kmHigh 21.3°C · Low 10.4°C · 95 mm rain
- Toms River in MayUnited States · 82 kmHigh 20.9°C · Low 12.4°C · 84 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Philadelphia) is explained once on the Philadelphia year overview and on the Sources, method and limits page.