Philadelphia climate
Philadelphia is warmest in July, with average highs of 30 °C, and coldest in January, when nights average -2.9 °C. September is the wettest month (106 mm) and November the driest (75 mm). Figures are 1991–2020 climate normals.
Across a full year Philadelphia averages 1,119 mm of rain, 110 days above 25 °C and 78 days below freezing.
United States · 12 m elevation · population 1,573,916 · 1991–2020 normals
Temperature below 0 °C to above 30 °C Rain band height is that month’s share of the wettest month
- Warmest month July 30 °C
- Coldest month January -2.9 °C
- Driest month November 75 mm
- Wettest month September 106 mm
- Least cloud October 50 % cloud
- Hottest on record July 40 °C
- Coldest on record January -23 °C
What to expectPhiladelphia through the year
Philadelphia has a clear annual cycle: average daily highs run from 4.8 °C in January to 30 °C in July, a swing of 25 °C in mean temperature across the year.
Counted across a normal year, 110 days a year reach 25 °C, 39 of them reach 30 °C, 78 nights drop below freezing. The warmest reading in the 1991–2020 record is 40 °C, in July.
Rain is spread fairly evenly through the year, from 75 mm in November to 106 mm in September. There is no dry season to aim for.
Month by month
| Month | Avg high | Rainfall | Cloud |
|---|---|---|---|
| January | 4.8 °C | 83 mm | 58 % |
| February | 6.5 °C | 75 mm | 57 % |
| March | 11.0 °C | 104 mm | 59 % |
| April | 17.5 °C | 92 mm | 59 % |
| May | 22.6 °C | 91 mm | 60 % |
| June | 27.4 °C | 102 mm | 58 % |
| July | 30.1 °C | 99 mm | 54 % |
| August | 28.9 °C | 97 mm | 53 % |
| September | 25.2 °C | 106 mm | 52 % |
| October | 18.8 °C | 94 mm | 50 % |
| November | 12.6 °C | 75 mm | 55 % |
| December | 7.3 °C | 102 mm | 59 % |
Temperature month by month
| Month | Avg high | Avg low | Mean | Record high | Record low | Days above 25 °C | Days above 30 °C | Days below 0 °C |
|---|---|---|---|---|---|---|---|---|
| January | 4.8 °C | -2.9 °C | 0.5 °C | 21.0 °C | -22.7 °C | 0 | 0 | 22 |
| February | 6.5 °C | -2.4 °C | 1.4 °C | 23.5 °C | -22.6 °C | 0 | 0 | 20 |
| March | 11.0 °C | 1.2 °C | 5.6 °C | 29.3 °C | -16.8 °C | 0 | 0 | 13 |
| April | 17.5 °C | 6.9 °C | 11.7 °C | 32.8 °C | -2.4 °C | 2 | 0 | 1 |
| May | 22.6 °C | 12.4 °C | 17.1 °C | 33.8 °C | 0.3 °C | 9 | 2 | 0 |
| June | 27.4 °C | 17.7 °C | 22.3 °C | 37.7 °C | 8.9 °C | 22 | 7 | 0 |
| July | 30.1 °C | 20.7 °C | 25.1 °C | 39.9 °C | 13.5 °C | 30 | 15 | 0 |
| August | 28.9 °C | 19.9 °C | 24.1 °C | 38.1 °C | 12.8 °C | 28 | 11 | 0 |
| September | 25.2 °C | 16.4 °C | 20.5 °C | 34.9 °C | 6.3 °C | 16 | 3 | 0 |
| October | 18.8 °C | 10.2 °C | 14.0 °C | 34.4 °C | -0.2 °C | 3 | 0 | 0 |
| November | 12.6 °C | 4.6 °C | 8.0 °C | 25.0 °C | -8.3 °C | 0 | 0 | 5 |
| December | 7.3 °C | 0.0 °C | 3.2 °C | 23.4 °C | -14.9 °C | 0 | 0 | 16 |
Rain, sun and wind month by month
| Month | Rainfall | Wet days | Daylight | Cloud cover | Humidity | Wind |
|---|---|---|---|---|---|---|
| January | 83 mm | 9 | 9.7 h/day | 58 % | 66 % | 19 km/h |
| February | 75 mm | 9 | 11 h/day | 57 % | 65 % | 20 km/h |
| March | 104 mm | 10 | 12 h/day | 59 % | 64 % | 20 km/h |
| April | 92 mm | 10 | 13 h/day | 59 % | 65 % | 20 km/h |
| May | 91 mm | 11 | 14 h/day | 60 % | 68 % | 17 km/h |
| June | 102 mm | 11 | 15 h/day | 58 % | 69 % | 16 km/h |
| July | 99 mm | 11 | 15 h/day | 54 % | 68 % | 15 km/h |
| August | 97 mm | 11 | 14 h/day | 53 % | 70 % | 14 km/h |
| September | 106 mm | 9 | 12 h/day | 52 % | 71 % | 15 km/h |
| October | 94 mm | 8 | 11 h/day | 50 % | 71 % | 17 km/h |
| November | 75 mm | 8 | 10.0 h/day | 55 % | 69 % | 18 km/h |
| December | 102 mm | 9 | 9.4 h/day | 59 % | 70 % | 18 km/h |
Where Philadelphia ranks
| Ranking | Position | Value |
|---|---|---|
| Places with the best weather in North America in May | 38thof 50 | 88/100 |
Planning a trip? See the best time to visit Philadelphia.
QuestionsCommon questions about Philadelphia’s climate
When is the best time to visit Philadelphia?
That depends on what you want, so the honest answer is a comparison rather than a single month. May, June, September sit closest to 20 °C on average, July is the warmest month and November the driest. The month-by-month table above has the full picture.
How hot does Philadelphia get?
In July, the warmest month, daily highs average 30 °C. About 39 days a year pass 30 °C. The highest value in the 1991–2020 record is 40 °C.
How cold does it get in winter?
Nights average -2.9 °C in January, the coldest month. A normal year has 78 nights below freezing.
Which month is wettest in Philadelphia?
September, averaging 106 mm over 9 days with rain. The driest month is November with 75 mm. The year as a whole averages 1,119 mm.
Are these figures a forecast?
No. They are 1991–2020 climate normals: the average of thirty years, which describes what a month is usually like in Philadelphia rather than what any particular week will bring. Individual years can differ substantially from the normal.
Data sources and method
- ERA5 / ERA5-Land reanalysis — Copernicus Climate Change Service (C3S), ECMWF. Copernicus Licence
- Open-Meteo — Open-Meteo.com. CC BY 4.0
- NOAA OISST v2.1 — NOAA Physical Sciences Laboratory. Public domain
- GeoNames — GeoNames.org. CC BY 4.0
- Normal period
- 1991–2020
- Dataset version
- era5-1991-2020-scores1.1
- Last processed
Measured values come from ERA5 reanalysis and are reproduced unchanged. Calculated by us: monthly rankings, daylight hours, beach and comfort scores. Full formulas are on the methodology page.
Contains modified Copernicus Climate Change Service information 2026. Neither the European Commission nor ECMWF is responsible for any use that may be made of the Copernicus information or data it contains.