San Diego has the kind of weather people move across the country for. The city averages 262 mm (10.3 in) of rain a year and roughly 260 sunny or partly sunny days, with daytime highs that hold between 18°C and 25°C almost every month. This guide breaks down San Diego weather by month with real numbers, so you know exactly what to pack and when to book. For the full picture across seasons, see the complete San Diego weather guide.
San Diego Weather by Month: Climate at a Glance
San Diego sits on the Pacific coast at 32°N, and its Mediterranean climate (Köppen Csb) is driven by the cold California Current offshore. The ocean keeps winters mild and summers cooler than inland areas like El Cajon or Escondido, which sit 15 to 20 km east and regularly run 5 to 8°C warmer in summer. Annual rainfall is only 262 mm (10.3 in), almost all of it falling between November and March. Microclimates vary sharply by San Diego neighborhood: the coast stays cool and overcast while inland valleys bake.
| Month | Avg High | Avg Low | Rainfall |
|---|---|---|---|
| January | 18.6°C (66°F) | 9.8°C (50°F) | 51 mm (2.0 in) |
| February | 18.9°C (66°F) | 10.5°C (51°F) | 57 mm (2.2 in) |
| March | 19.2°C (67°F) | 11.6°C (53°F) | 46 mm (1.8 in) |
| April | 20.2°C (68°F) | 13.0°C (55°F) | 20 mm (0.8 in) |
| May | 20.6°C (69°F) | 15.0°C (59°F) | 3 mm (0.1 in) |
| June | 22.0°C (72°F) | 16.7°C (62°F) | 2 mm (0.1 in) |
| July | 24.0°C (75°F) | 18.5°C (65°F) | 1 mm (0.03 in) |
| August | 25.0°C (77°F) | 19.2°C (67°F) | 1 mm (0.03 in) |
| September | 24.8°C (77°F) | 18.4°C (65°F) | 4 mm (0.15 in) |
| October | 23.1°C (74°F) | 15.6°C (60°F) | 12 mm (0.5 in) |
| November | 21.0°C (70°F) | 11.9°C (53°F) | 26 mm (1.0 in) |
| December | 18.6°C (65°F) | 9.4°C (49°F) | 41 mm (1.6 in) |
San Diego Weather in Winter: December to February
Winter is San Diego’s rainy season, but ‘rainy’ is relative. December averages 41 mm (1.6 in) and February 57 mm (2.2 in), usually spread across 5 to 7 wet days per month. Highs hold at 18 to 19°C (66°F) and lows drop to 9 to 10°C (49 to 50°F). You’ll want a light jacket after sunset, but daytime beach walks are common. January and February bring the year’s lowest hotel rates outside the holidays, and the San Diego travel tips guide covers what to pack for the coolest stretch.
San Diego Weather in Spring: March to May
March and April warm slowly, with highs climbing from 19°C to 20°C (67 to 68°F) and rainfall dropping from 46 mm in March to 20 mm in April. May is when the marine layer arrives: locals call it ‘May Gray,’ a low overcast that hugs the coast most mornings and burns off by early afternoon. Inland neighborhoods clear hours earlier than the beaches. For crowd and price patterns across these months, see the best time to visit San Diego guide.
San Diego Weather in Summer: June to August
‘June Gloom’ is the famous low cloud deck that can linger until midday near the coast, keeping mornings cool at 16 to 17°C (62°F). By July and August the gloom fades and highs reach 24 to 25°C (75 to 77°F), with almost no rain, under 5 mm for the whole season. This is peak beach weather and the busiest period, so book rooms early and check the where to stay in San Diego guide for area-by-area advice.
San Diego Weather in Fall: September to November
September is often the warmest-feeling month, with highs around 25°C (77°F) and the ocean at its warmest. October brings Santa Ana winds, hot dry offshore gusts that can push coastal temperatures into the 30s°C (90s°F) and raise wildfire risk. Rainfall stays low through October (12 mm) before November jumps to 26 mm (1.0 in). Fall is the best-value season: fewer crowds than summer and reliably sunny days, and the San Diego events calendar has the autumn festival dates.
San Diego Weather by Month: Ocean Water Temperatures
The Pacific off San Diego is cool all year because of the California Current. Ocean temperatures range from 15°C (59°F) in February to 21°C (70°F) in August and September. Most swimmers wear wetsuits outside July through September. Surfers, kayakers in La Jolla Cove, and snorkelers planning things to do in San Diego should expect water this cold even on hot days.
- January to March: 15 to 15.5°C (59 to 60°F)
- April to June: 16 to 18°C (61 to 65°F)
- July to September: 20 to 21°C (68 to 70°F)
- October to December: 16 to 19°C (60 to 66°F)
