San Diego weather by month
San Diego runs from about 13°C in January to 22°C in August, with February the wettest month at 145 mm.
warmest month
August
22°C
coolest month
January
13°C
wettest month
February
145 mm
worst air month
March
23 µg/m³
The whole year, month by month.
| Month | Avg temp | Rain | Sun | PM2.5 |
|---|---|---|---|---|
| January | 13°C | 96 mm | 267 h | 19 |
| February | 13°C | 145 mm | 229 h | 19 |
| March | 14°C | 107 mm | 318 h | 23 |
| April | 15°C | 10 mm | 326 h | 14 |
| May | 16°C | 1 mm | 356 h | 13 |
| June | 19°C | 0 mm | 360 h | 12 |
| July | 21°C | 0 mm | 379 h | 13 |
| August | 22°C | 0 mm | 363 h | 20 |
| September | 21°C | 2 mm | 322 h | 15 |
| October | 19°C | 2 mm | 308 h | 18 |
| November | 15°C | 4 mm | 285 h | 21 |
| December | 13°C | 1 mm | 273 h | 23 |
About 3,786 hours of sun a year. Roughly 37 rainy days a year.
These are long-run climate normals, not a forecast. A given year can sit well outside them. PM2.5 is a global model: near the coast it counts sea salt as fine particulate and reads high against ground stations, sometimes by a factor of two. Use the shape of the year, not the absolute number.
where these numbers come from
- · Temperature, rainfall and sunshine: ECMWF ERA5 reanalysis climate normals via Open-Meteo (CC BY 4.0), fetched once and stored.
- · PM2.5: Copernicus CAMS reanalysis, monthly means. Modelled, not station readings; near coasts CAMS counts sea salt as PM2.5 and reads high.
Last reviewed 2026-05-23. Full method, licences and the list of sources we rejected are on the methodology page.