Climate averages 1991–2020
Philadelphia weather
in January.
A cold, moderately wet month: the coolest and the 3rd driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
January is a cold month in Philadelphia: daytime highs average 4.5°C and nights cool to about -3.3°C. By daytime temperature it is the coolest month of the year.
Expect about 82 mm of rain on roughly 9 days, which makes January a moderately wet month (the 3rd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 9 h 41 min on an average January day.
The nearest other city in this atlas is Camden (5 km away). In January its highs average 4.7°C, about as warm as Philadelphia, with 81 mm of rain.
Among the 498 cities listed in the United States, Philadelphia ranks joint 332nd of 498 for the warmest January highs and joint 290th of 498 for the driest January (rainfall, lowest first). The mean January high of those 498 cities is 9.5°C; Philadelphia is 5.0°C cooler than that mean.
From January to February, average highs rise by 1.6°C to 6.2°C, and monthly rainfall falls from 82 mm to 76 mm.
The annual picture
January 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, selected | 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
January in nearby cities
- Camden in JanuaryUnited States · 5 kmHigh 4.7°C · Low -3.2°C · 81 mm rain
- Cherry Hill in JanuaryUnited States · 11 kmHigh 4.6°C · Low -3.0°C · 81 mm rain
- Wilmington (Delaware), United States in JanuaryUnited States · 40 kmHigh 4.5°C · Low -3.0°C · 82 mm rain
- Trenton in JanuaryUnited States · 46 kmHigh 4.2°C · Low -3.8°C · 83 mm rain
- Bethlehem, United States in JanuaryUnited States · 77 kmHigh 2.8°C · Low -5.7°C · 90 mm rain
- Reading, United States in JanuaryUnited States · 78 kmHigh 3.4°C · Low -4.4°C · 82 mm rain
- Allentown in JanuaryUnited States · 78 kmHigh 2.8°C · Low -5.7°C · 87 mm rain
- Toms River in JanuaryUnited States · 82 kmHigh 4.7°C · Low -2.3°C · 83 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.