expatwhy.

Philadelphia weather by month

Philadelphia runs from about 2°C in January to 27°C in July, with August the wettest month at 204 mm.

warmest month

July

27°C

coolest month

January

2°C

wettest month

August

204 mm

worst air month

February

24 µg/m³

The whole year, month by month.

Monthly climate normals for Philadelphia
MonthAvg tempRainSunPM2.5
January2°C163 mm161 h13
February3°C61 mm225 h24
March8°C181 mm244 h11
April12°C106 mm269 h10
May18°C88 mm263 h11
June25°C83 mm380 h12
July27°C52 mm351 h14
August24°C204 mm331 h16
September20°C19 mm257 h14
October15°C2 mm307 h8
November10°C74 mm233 h12
December3°C95 mm197 h13

About 3,218 hours of sun a year. Roughly 112 rainy days a year.

These are long-run climate normals, not a forecast. A given year can sit well outside them. PM2.5 is a global model: near the coast it counts sea salt as fine particulate and reads high against ground stations, sometimes by a factor of two. Use the shape of the year, not the absolute number.