Solar energy in St. Louis, United States
Average irradiation 4.17 kWh/m²/day · ~1218 kWh per kWp per year
Monthly solar irradiation & temperature in St. Louis (NASA POWER)
| Month | Irradiation (kWh/m²/day) | Avg temp (°C) | Est. production per kWp (kWh) |
|---|---|---|---|
| Jan | 2.09 | -1.0 | 51 |
| Feb | 2.80 | 0.6 | 68 |
| Mar | 3.76 | 6.9 | 91 |
| Apr | 5.03 | 13.3 | 122 |
| May | 5.64 | 18.7 | 137 |
| Jun | 6.42 | 23.7 | 156 |
| Jul | 6.28 | 25.8 | 153 |
| Aug | 5.57 | 25.0 | 135 |
| Sep | 4.75 | 21.0 | 116 |
| Oct | 3.44 | 13.8 | 84 |
| Nov | 2.40 | 6.9 | 58 |
| Dec | 1.81 | 1.4 | 44 |
Solar potential of St. Louis explained
St. Louis receives an average of 4.17 kilowatt-hours of solar energy per square metre per day, measured over four decades of satellite observation. In practical terms, every kilowatt-peak of installed PV capacity yields about 1218 kWh of electricity per year here, assuming a well-oriented system with a typical 80% performance ratio. This is a solid mid-range solar resource: production is meaningful year-round, though winter output drops noticeably.
Frequently asked questions
Is solar worth it in St. Louis?
With 4.17 kWh/m²/day of average irradiation, a 1 kWp system in St. Louis produces roughly 1218 kWh per year. That is a good solar resource; with current panel prices most systems pay back well within their lifetime.
How much electricity would a 5 kW system produce in St. Louis?
Approximately 6,000 kWh per year — enough to cover a large share of a typical household's consumption.
What data is this based on?
Long-term satellite observations from NASA POWER (1981–present) and the PVGIS SARAH3 database, assuming a performance ratio of 80%.
Compare with nearby cities
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