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The air is 72°F all year. The water is not — and that surprises almost every first-time visitor.
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San Diego ocean temperatures run roughly 58–62°F in winter and early spring, climb through the 60s in late spring, and peak at about 68–72°F in August and September. That means the warmest ocean swimming of the year comes at the end of summer, not the start. Most locals wear a wetsuit from roughly October through June — a 3/2 full suit in the coldest months and a spring suit in the shoulder season — and surf in trunks only in August and September. Visitors from the Atlantic coast or the Gulf routinely find June water shockingly cold at around 65°F. Bays warm faster than the open coast, so Mission Bay and the Children's Pool feel several degrees friendlier than Black's or Torrey Pines.
| Month | Typical water temp | What to wear |
|---|---|---|
| January | 58–60°F | 3/2 full wetsuit |
| February | 58–60°F | 3/2 full wetsuit |
| March | 59–61°F | 3/2 full wetsuit |
| April | 61–63°F | Full suit or spring suit |
| May | 62–64°F | Spring suit |
| June | 64–67°F | Spring suit · brief swims in trunks |
| July | 67–69°F | Trunks for most people |
| August | 68–72°F | Warmest of the year |
| September | 68–71°F | Still warm, fewer crowds |
| October | 65–68°F | Spring suit returns |
| November | 62–64°F | Spring suit or full |
| December | 59–61°F | 3/2 full wetsuit |
Averages hide the two things that actually change your day: upwelling and where you swim.
Open coast · Spring especially
Northwest winds push surface water offshore and cold water rises to replace it. A 64°F week in May can become a 58°F week with no warning. It's the reason locals keep a wetsuit through summer.
Mission Bay, San Diego Bay · +3 to 6°F
Shallow, sheltered water heats up. Mission Bay in July often feels like a swimming pool compared with Pacific Beach 200 yards away, which makes it the right pick for small kids.
Coronado, La Jolla Shores · Shelter matters
Beaches tucked out of the northwest wind — La Jolla Shores, Coronado, Children's Pool — feel notably warmer than exposed stretches like Torrey Pines or Black's on the same day.
What locals actually wear, by season.
All beaches · 58–61°F
A 3/2mm full suit is standard. Booties are optional; most people skip them, and a hood is overkill in San Diego.
All beaches · 61–67°F
A short-arm spring suit covers most sessions. Bring the full suit anyway in May — upwelling weeks bite.
All beaches · 65–72°F
Trunks work for swimming and short surfs. A spring suit still helps on a long session or an early morning.
Beach towns · Roughly $15–25/day
Surf shops in Pacific Beach, Mission Beach, La Jolla and Encinitas rent suits by the day, usually bundled with a board.
Temperature isn't the only variable.
Coastwide · Irregular, often spring and late summer
Algal blooms turn the water rust-brown by day and can make the waves glow blue at night. It's usually harmless to swim through, though it can irritate eyes and smells strongly as it decays.
River mouths and bays · Wait 72 hours
Runoff pushes bacteria into the ocean after storms. County advisories recommend staying out of the water for about 72 hours after significant rain, especially near river mouths like the San Dieguito and the Tijuana River.
Sandy-bottom beaches · Warmer months
Shuffle your feet in the shallows from late spring through fall. The stingray shuffle genuinely works, and the lifeguard towers keep hot-water buckets for the people who forgot.
It averages about 58–62°F in winter and 68–72°F at the late-summer peak in August and September. Even in June, water in the mid-60s feels cold to most visitors.
Most locals wear one from October through June — a 3/2 full suit in winter and a spring suit in the shoulder seasons. July through September, trunks are fine for most people.
Late August through mid-September, when temperatures reach roughly 68–72°F. September is the best combination of warm water and thinner crowds all year.
Usually, yes — around 64–67°F, and cooler during an upwelling week. June also brings the marine layer, so the beach can be grey and the water brisk at the same time.
Mission Bay and San Diego Bay run several degrees warmer than the open coast, and sheltered spots like La Jolla Shores, the Children's Pool and Coronado feel warmer than exposed beaches such as Torrey Pines.
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Written and fact-checked by the Sandi Spots Editorial team — San Diego residents publishing under Sleep Coast LLC. Every place we recommend has been visited in person or verified against an official source, and no business can pay for inclusion or a higher ranking. Last updated .