Is today a good day for sea swimming in San Francisco?
Today is not the day.
Not safe for sea swimming today. A 1.3 m sea running. Out of season for it, whatever the weather does.
Not today14/100
7-day outlook for sea swimming in San Francisco
Best day looks like Today at 14/100.
Why this score?
Data from Open-Meteo, and Open-Meteo Marine for waves and sea temperature. Last updated 21:34 UTC.
Sea swimming in San Francisco, month by month
The sea is warmest in September at 16°C and coldest in March at 12°C. Offshore waves are biggest in January (the day's highest averages 1.8 m) and smallest in July (1.0 m). Daytime highs peak at 21°C in October and fall to 14°C in December. December is the wettest month, with about 12 days of 1 mm or more; July is the driest, with about 0.
Our seasonal guide puts sea swimming in season from May to October.
| Month | Sea temperature (°C) | Offshore wave height (m) | Daytime high (°C) | Rainy days (days) |
|---|---|---|---|---|
| January | 12 | 1.8 | 14 | 11 |
| February | 12 | 1.8 | 15 | 6 |
| March | 12 | 1.6 | 14 | 11 |
| April | 13 | 1.5 | 16 | 3 |
| May (in season) | 13 | 1.4 | 18 | 3 |
| June (in season) | 14 | 1.3 | 19 | 0 |
| July (in season) | 15 | 1.0 | 19 | 0 |
| August (in season) | 16 | 1.0 | 20 | 0 |
| September (in season) | 16 | 1.1 | 21 | 1 |
| October (in season) | 16 | 1.2 | 21 | 3 |
| November | 13 | 1.4 | 16 | 7 |
| December | 12 | 1.7 | 14 | 12 |
In season, by our seasonal guide
Averages of daily weather 2020 to 2024 and of waves and sea temperature 2022 to 2024, from ERA5 reanalysis data (about 25 km resolution; waves are measured offshore, not in the surf at the beach). Not a forecast.
About sea swimming in San Francisco
Microclimates that change in five minutes, year-round wetsuit-only sea swimming, and Marin Headlands on the doorstep.
Go Daisy scores 47 activities for San Francisco, including running, cycling, urban exploring, photography, outdoor yoga. The score for sea swimming updates hourly from the same weather data professional services use.
Also today in San Francisco
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Score for sea swimming in San Francisco updated hourly. Free, ad-free. Built by independent makers in the UK and Asturias, Spain.
Weather data from Open-Meteo.