Solar energy in Seattle, USA
Average irradiation 3.41 kWh/m²/day · ~996 kWh per kWp per year
Monthly solar irradiation & temperature in Seattle (NASA POWER)
| Month | Irradiation (kWh/m²/day) | Avg temp (°C) | Est. production per kWp (kWh) |
|---|---|---|---|
| Jan | 1.03 | 4.4 | 25 |
| Feb | 1.92 | 4.6 | 47 |
| Mar | 2.85 | 6.7 | 69 |
| Apr | 4.15 | 9.0 | 101 |
| May | 5.25 | 12.8 | 128 |
| Jun | 5.73 | 15.2 | 139 |
| Jul | 6.33 | 18.2 | 154 |
| Aug | 5.40 | 18.3 | 131 |
| Sep | 3.91 | 15.4 | 95 |
| Oct | 2.28 | 10.8 | 55 |
| Nov | 1.22 | 6.7 | 30 |
| Dec | 0.85 | 3.8 | 21 |
Solar potential of Seattle explained
Seattle receives an average of 3.41 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 996 kWh of electricity per year here, assuming a well-oriented system with a typical 80% performance ratio. While winters are dark, modern panel prices mean solar can still be economical — self-consumption value matters more than raw sunshine here.
Frequently asked questions
Is solar worth it in Seattle?
With 3.41 kWh/m²/day of average irradiation, a 1 kWp system in Seattle produces roughly 996 kWh per year. That is a moderate solar resource; economics depend more on local electricity prices and incentives, which our AI planner can research for you.
How much electricity would a 5 kW system produce in Seattle?
Approximately 5,000 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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