Calculator › San Diego, California
Solar panels in San Diego, California
San Diego receives 4.88 peak sun hours a day and 1,782 kWh/m² of solar energy a year. That is measured satellite data for San Diego's coordinates, not a national average — and it changes the panel count.
San Diego solar data
4.88peak sun hours/day
1,782annual irradiance (kWh/m²)
1.61kWh/day from one 400 W panel
588kWh/year from one 400 W panel
Monthly solar irradiance in San Diego
| Month | Peak sun hours/day | Share of year |
|---|---|---|
| January | 3.18 | 0.3 |
| February | 3.76 | 0.3 |
| March | 5.38 | 0.4 |
| April | 6.17 | 0.5 |
| May | 5.46 | 0.5 |
| June | 5.84 | 0.5 |
| July | 6.08 | 0.5 |
| August | 6.60 | 0.5 |
| September | 5.29 | 0.4 |
| October | 4.09 | 0.3 |
| November | 3.81 | 0.3 |
| December | 2.73 | 0.2 |
Source: NASA POWER daily point API, parameter ALLSKY_SFC_SW_DWN (global horizontal irradiance), year 2024. Coordinates 32.7157, -117.1611.
How many solar panels does San Diego need?
For a typical US household using 900 kWh a month, San Diego needs about 19 panels of 400 W (7.45 kWp), with a south-facing roof. That is fewer panels than the same household would need in a city with 4.5 peak sun hours.