Climate averages 1991–2020
Philadelphia weather
by month.
See how the year changes. July has the highest average daily maximum; November has the lowest average monthly rainfall.
Long-term climate patterns, not a forecast for a particular trip.
Across the year Philadelphia averages a daytime high of 17.5°C and a nighttime low of 8.5°C, with about 1,102 mm of rain on roughly 116 days. July is the warmest month (average high 29.9°C) and January the coolest (4.5°C). September (tied with March) is the wettest month with 104 mm; November is the driest with 74 mm.
The annual picture
A year in Philadelphia
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 | 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
Nearby cities
- CamdenUnited States · 5 kmHigh 17.5°C · Low 8.5°C · 1,083 mm rain a year
- Cherry HillUnited States · 11 kmHigh 17.4°C · Low 8.7°C · 1,083 mm rain a year
- Wilmington (Delaware), United StatesUnited States · 40 kmHigh 17.2°C · Low 8.6°C · 1,117 mm rain a year
- TrentonUnited States · 46 kmHigh 17.1°C · Low 7.9°C · 1,127 mm rain a year
- Bethlehem, United StatesUnited States · 77 kmHigh 16.1°C · Low 6.3°C · 1,153 mm rain a year
- Reading, United StatesUnited States · 78 kmHigh 16.8°C · Low 7.5°C · 1,094 mm rain a year
- AllentownUnited States · 78 kmHigh 16.2°C · Low 6.4°C · 1,148 mm rain a year
- Toms RiverUnited States · 82 kmHigh 16.9°C · Low 9.3°C · 1,117 mm rain a year
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 limitsWhat do the high and low temperatures mean?
We average the daily maximum and daily minimum for each calendar month over 1991–2020. They are not record extremes, a forecast range or temperatures at a fixed time of day.
How is a rain day counted?
A local calendar day (standard time, UTC-5, no daylight saving) with at least 1 mm of total precipitation counts as one rain day. We count these for each year and month, then average across 30 years. The average does not predict which days will be wet.
Where do the numbers come from?
ERA5-Land (temperature) and ERA5 (precipitation) reanalysis from the Copernicus Climate Change Service, read from the Open-Meteo open-data archive. Temperature comes from the 0.1° model cell at 40.00°, -75.20° (6 km from the city centre), adjusted up by 0.2°C for the difference between the city's elevation (8 m) and the cell's (44 m). Rain comes from the 0.25° cell at 40.00°, -75.25°. These are model estimates, not weather-station readings; coast, hills and city streets can differ.
Does this page show sunshine, humidity or sea temperature?
No. The data used here contain air temperature and precipitation only. Daylight hours are calculated from the city's latitude (sunrise to sunset), not measured sunshine.