Philadelphia is warmest in July, averaging 31° by day and 20° at night. The wettest month is July with 127 mm, and the year brings about 1210 mm in total.
Month by month
| Month | High | Low | Rain | Sea | Daylight | Good for |
|---|---|---|---|---|---|---|
| January | 5° | -5° | 90 mm | 4° | 9.5 h | Cool |
| February | 7° | -4° | 67 mm | 3° | 10.4 h | Cool |
| March | 12° | -1° | 102 mm | 6° | 11.7 h | Mild |
| April | 17° | 5° | 111 mm | 11° | 13.1 h | Mild |
| May | 22° | 11° | 78 mm | 16° | 14.2 h | Sightseeing |
| June | 27° | 16° | 102 mm | 22° | 14.8 h | Beach weather |
| July | 31° | 20° | 127 mm | 27° | 14.6 h | Mild |
| August | 30° | 19° | 127 mm | 26° | 13.6 h | Mild |
| September | 26° | 15° | 108 mm | 24° | 12.2 h | Mild |
| October | 21° | 9° | 90 mm | 18° | 10.9 h | Sightseeing |
| November | 14° | 2° | 90 mm | 12° | 9.7 h | Mild |
| December | 8° | -1° | 118 mm | 6° | 9.2 h | Cool |
High and low are average daily maximum and minimum, rain is typical monthly total, sea is the average surface temperature, daylight is the hours between sunrise and sunset mid-month. Climate normals from NASA POWER and NOAA MUR — averages, not promises.
When to go
Beach weather: June — highs around 27°, nights no colder than 16°, and at most 102 mm of rain in a month. The sea sits at 22–22° then.
Walking the city: May and October — highs of 21–22° and no more than 90 mm of rain a month.