Best Time to Visit Philadelphia
The best time to visit Philadelphia is May to September, when the average temperature is 17–25°C and rainfall is low for Philadelphia, at 96–124 mm a month.
Philadelphia weather by month
The wettest month in Philadelphia is July with 124 mm of rain, and the warmest is July at an average 25°C. The coolest is January at -1°C.
| Month | Average temperature | Rainfall | Verdict |
|---|---|---|---|
| January | -1°C / 30°F | 78 mm | Cold |
| February | 0°C / 32°F | 78 mm | Cold |
| March | 5°C / 40°F | 100 mm | Cool |
| April | 11°C / 51°F | 97 mm | Cool |
| May | 17°C / 62°F | 96 mm | Best |
| June | 22°C / 71°F | 121 mm | Best |
| July | 25°C / 76°F | 124 mm | Best |
| August | 24°C / 75°F | 121 mm | Best |
| September | 20°C / 69°F | 102 mm | Best |
| October | 14°C / 56°F | 110 mm | Cool |
| November | 7°C / 45°F | 90 mm | Cool |
| December | 2°C / 36°F | 111 mm | Cold |
How we pick the best months
- Best: an average temperature of 15–28°C and low rainfall for Philadelphia: under 150 mm, and no more than 126 mm, a quarter above Philadelphia's median month (never set below 60 mm).
- If no month qualifies, we show the three driest months that average 10–30°C instead.
- Wet: 150 mm of rain or more. Rainy: more than 126 mm. Hot: 29°C or more on average. Cool: under 15°C. Cold: under 5°C.
Averages cover day and night, so afternoons are warmer than the figure shown. Weather is only one reason to pick a month: school holidays, festivals and prices matter too.
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Where these numbers come from
Monthly averages for January 2001 – December 2020 from the NASA POWER project, for the area around Philadelphia International (PHL) at 39.87, -75.24. The model covers a grid about 50 km across, so a coastal or hilly spot can run a degree or two different. Retrieved 12 September 2026.
The data was obtained from the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) Prediction of Worldwide Energy Resource (POWER) Project funded through the NASA Earth Science/Applied Science Program.