WeatherArchive / Compare cities / San Diego vs Seattle
San Diego vs Seattle weather: climate comparison
San Diego is the warmer of the two, averaging 63°F (17°C) over the year against 52°F (11°C) in Seattle. Seattle is wetter, with 50.2 in (1275 mm) of precipitation a year to San Diego's 11.7 in (298 mm). Below: every month side by side, from 30 years of ERA5 data (1996–2025).
- Mean temperature
- 17.0°C San Diego
10.9°C Seattle - Annual precipitation
- 298.4 mm San Diego
1274.6 mm Seattle - Rainy days a year
- 38 San Diego
154 Seattle - Sunshine per day
- 10.9 h San Diego
8.3 h Seattle
Month by month
| Month | San Diego | Seattle |
|---|---|---|
| January | 17.5°C | 7.3°C |
| February | 17.3°C | 8.4°C |
| March | 17.8°C | 10.6°C |
| April | 19.1°C | 13.4°C |
| May | 20.2°C | 16.9°C |
| June | 21.9°C | 20.0°C |
| July | 24.3°C | 24.0°C |
| August | 25.3°C | 24.2°C |
| September | 25.0°C | 20.4°C |
| October | 23.1°C | 14.6°C |
| November | 20.4°C | 9.8°C |
| December | 17.5°C | 6.9°C |
Year at a glance
| Measure | San Diego | Seattle |
|---|---|---|
| Mean annual temperature | 17.0°C | 10.9°C |
| Warmest month (avg high) | Aug · 25°C | Aug · 24°C |
| Coldest month (avg low) | Jan · 9°C | Feb · 2°C |
| Annual range (warmest high − coldest low) | 17°C | 22°C |
| Annual precipitation | 298.4 mm | 1274.6 mm |
| Rainy days per year | 38 | 154 |
| Wettest / driest month | Feb / Jun | Nov / Jul |
| Average sunshine per day | 10.9 h | 8.3 h |
In short: San Diego is the warmest overall (17.0°C mean); Seattle gets the most precipitation (1274.6 mm a year); San Diego is the sunniest (10.9 h a day on average); San Diego has the smallest swing between its warmest and coldest months.
Record high 1996–2025: San Diego 36.6°C (2020-09-30), Seattle 37.9°C (2021-06-28). Record low: San Diego 1.8°C (2007-01-15), Seattle -14.5°C (1996-01-30).
Source: Open-Meteo Historical Weather API (CC BY 4.0). Values are ERA5 reanalysis model data on a ~9–25 km grid, not readings from a weather station, so a single town’s thermometer can differ by a few degrees and local showers can be missed. Monthly means of daily ERA5 values, 1996–2025, for the grid cells nearest San Diego (32.72, -117.14) and Seattle (47.63, -122.32).
Which months differ most?
The gap in average highs is widest in December, when San Diego runs 19°F / 11°C warmer, and narrowest in July (0°F / 0°C apart). The biggest rainfall difference is in November: Seattle gets 6.4 in (162 mm) more on average.
Add a third or fourth city, or swap in any other place, in the full comparison tool. For one city in depth, see the San Diego climate and Seattle climate pages.
Compare San Diego or Seattle with another city
Questions people ask
Is San Diego warmer than Seattle?
San Diego is warmer on average: its mean annual temperature is 63°F (17°C) against 52°F (11°C) in Seattle (ERA5, 1996–2025).
Which gets more rain, San Diego or Seattle?
Seattle, with about 50.2 in (1275 mm) of precipitation a year and 154 days with at least 1 mm, compared with 11.7 in (298 mm) and 38 days in San Diego.
Which is sunnier, San Diego or Seattle?
San Diego averages more sunshine: 10.9 h a day against 8.3 h. Sunshine duration is modelled from cloud cover.
How reliable is this comparison?
Both cities use the same 30-year reanalysis, so differences are consistent. Absolute values describe a grid cell several kilometres wide and can differ by a degree or two from the airport station.