Direct answer
How cold does it get in San Diego?
Quick answer
San Diego winters average highs of 64–67°F and lows of 48–52°F on the coast, with December and January the coldest months. Inland valleys like El Cajon and Ramona drop into the 30s overnight, and the mountains near Julian get frost and occasional snow. Freezing temperatures are rare at the coast.
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Key facts
Coast versus inland
The ocean keeps coastal neighborhoods mild all winter, rarely below the mid-40s. Drive 20 miles inland and nights get 10–15°F colder. Julian and the Laguna Mountains see frost regularly and light snow a few times most winters.
- Coastal: highs 64–67°F, lows 48–52°F
- Inland valleys: lows in the 30s and 40s
- Mountains: frost common, occasional snow
- Deserts: warm days, cold nights, big swings
Month-by-month winter planning: December to March
December and January are typically the coolest coastal months, with afternoons often in the mid-60s and evenings around 50°F. February remains cool and can be rainy; March begins to warm, but chilly marine air still makes evenings feel different from the daytime forecast. These are planning ranges, not a live prediction.
- December: light jacket for daytime, warmer layer after sunset; check holiday weather before coastal outings.
- January: plan whale watching and museum options as rain backups; bring a wind-resistant layer for the harbor.
- February: bring closed-toe shoes and a compact rain shell for variable winter storms.
- March: daytime layers work for sightseeing, but beaches and ocean water remain cool.
Coastal, inland and mountain temperatures are different trips
A coastal forecast for La Jolla or downtown does not describe evenings in El Cajon, Ramona or Julian. Inland areas often cool much faster after sunset, while mountain roads can require weather precautions when storms arrive. Use the National Weather Service zone forecast for your destination—not just a San Diego city forecast.
- Coast: pack a windproof extra layer for harbor cruises and evening beach walks.
- Inland valleys: bring a warmer jacket if staying out late, especially after a clear day.
- Julian and mountains: check road conditions, possible frost and any storm advisories before departing.
- Ocean swimming: check water temperature and surf, not just air temperature.
What to pack
A light jacket and one warm layer handles almost any winter day. Evenings on the water feel colder than the forecast suggests, so bring something windproof if you plan a harbor cruise or an oceanfront dinner.
Winter is still good travel weather
January and February deliver plenty of clear 65°F days between rain systems, hotel rates drop well below summer, and gray whale season peaks. The trade-off is cold ocean water and shorter daylight.
Related questions
Does it ever freeze in San Diego?
Almost never at the coast. Inland valleys and the mountains hit freezing several nights each winter.
Does it snow in San Diego?
Not in the city. Julian and the Laguna Mountains, about an hour inland, get light snow a few times most winters.
Is San Diego cold at night in summer?
Coastal evenings drop to the low 60s, so a light layer is useful even in August.
What is the coldest month in San Diego?
December and January are the coldest months, with coastal lows typically around 48–52°F.
Do I need a winter coat for San Diego?
Not for the coast. A light jacket plus one warm layer covers most winter days; bring something warmer only for inland or mountain trips such as Julian, or for evenings on the water.
Where can I check today's forecast?
The National Weather Service San Diego office (weather.gov/sgx) publishes the official forecast, including separate coastal, valley and mountain zones.
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