Calculator › Portland, Oregon
Solar panels in Portland, Oregon
Portland receives 3.77 peak sun hours a day and 1,374 kWh/m² of solar energy a year. That is measured satellite data for Portland's coordinates, not a national average — and it changes the panel count.
Portland solar data
3.77peak sun hours/day
1,374annual irradiance (kWh/m²)
1.25kWh/day from one 400 W panel
454kWh/year from one 400 W panel
Monthly solar irradiance in Portland
| Month | Peak sun hours/day | Share of year |
|---|---|---|
| January | 0.97 | 0.1 |
| February | 1.81 | 0.2 |
| March | 3.25 | 0.3 |
| April | 4.59 | 0.4 |
| May | 5.80 | 0.5 |
| June | 6.54 | 0.5 |
| July | 7.46 | 0.6 |
| August | 5.42 | 0.5 |
| September | 4.10 | 0.3 |
| October | 2.75 | 0.2 |
| November | 1.29 | 0.1 |
| December | 1.00 | 0.1 |
Source: NASA POWER daily point API, parameter ALLSKY_SFC_SW_DWN (global horizontal irradiance), year 2024. Coordinates 45.5152, -122.6784.
How many solar panels does Portland need?
For a typical US household using 900 kWh a month, Portland needs about 25 panels of 400 W (9.64 kWp), with a south-facing roof. That is more panels than the same household would need in a city with 4.5 peak sun hours.