Cloudy skies · Pennsylvania
How cloudy is Philadelphia?
In a typical year, the sky over Philadelphia is mostly cloudy or overcast about 50% of the time, and clear or nearly clear about 34%.
January is the cloudiest month, mostly cloudy about 55% of the time, and September the least cloudy, at about 44%. Across winter, December to February, it’s mostly cloudy about 54% of the time. That makes it the 28th cloudiest sky of the 116 US cities we track.
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The forecast for the next 48 hours has the sky mostly cloudy about 38% of the time.
Philadelphia is mostly cloudy almost exactly half the time, about 50%, which is the most even-handed thing this city has ever done.
Live 48-hour forecast from OpenWeatherMap, refreshed about every half hour. Alerts from the National Weather Service.
The sky at a glance
| Mostly cloudy or overcast, all year | 50% |
|---|---|
| Clear or nearly clear, all year | 34% |
| Mostly cloudy, December to February | 54% |
| Cloudiest month | January, 55% |
| Least cloudy month | September, 44% |
Shares of hours across a typical year. Mostly cloudy means at least five eighths of the sky covered; clear or nearly clear means two eighths or less.
Cities with about the same sky
- St. Louis, Missouri: mostly cloudy about 50% of the time
- Dayton, Ohio: mostly cloudy about 50% of the time
- Rockford, Illinois: mostly cloudy about 50% of the time
More about the weather here
Source: NOAA U.S. Climate Normals, hourly, 1991 to 2020, station USW00013739. Airport sensors see cloud up to about 12,000 feet, so thin high cloud isn’t counted.