Optimal solar panel angle in Philadelphia, PA
For a fixed rooftop installation in Philadelphia, the weather-adjusted optimal angle is 36° tilt facing 195° SSW. This generates approximately 1,714 kWh/m² per year. All numbers based on 2025 historical weather data.
| Textbook (clear sky) | Weather-adjusted | |
|---|---|---|
| Tilt | 39° | 36° |
| Azimuth | 180° S | 195° SSW |
| Annual generation | 1,714 kWh/m² | |
What this means
The textbook formula says to tilt your panels at 39° and face due south (180°). But Philadelphia's actual weather shifts the optimum to 36° tilt and 195° azimuth. The 15° westward azimuth shift is caused by morning cloud patterns that clear by afternoon.
These numbers are for a fixed-angle installation optimized across all 12 months. If you adjust your panels seasonally, you can gain an additional 3-5%. Read more in our seasonal adjustment analysis.
Run it for your exact address
This data is for Philadelphia city center. Your roof may be in a slightly different microclimate. Our calculator optimizes for your exact coordinates.
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