California (United States): where to swim in January?
California, in January: the sea is at 13.3 °C on average along the coast, from 11.4 °C to 15.5 °C depending on the spot. Where the water is warmest (15.5 °C), it is cool. Swimming is fine if you like cool water: you get used to it after a few minutes, especially in mild weather.
Sea temperature, month by month
| Month | Average temperature | Depending on the spot | Where it is warmest |
|---|---|---|---|
| January | 13.3 °C | 11.4 °C – 15.5 °C | cool |
| February | 13.1 °C | 10.9 °C – 15.4 °C | cool |
| March | 13.0 °C | 10.9 °C – 15.7 °C | cool |
| April | 12.8 °C | 10.7 °C – 15.8 °C | cool |
| May | 13.6 °C | 11.3 °C – 17.0 °C | cool |
| June | 14.4 °C | 11.6 °C – 18.4 °C | cool |
| July | 15.5 °C | 12.2 °C – 20.1 °C | pleasant |
| August | 16.6 °C | 13.4 °C – 20.6 °C | pleasant |
| September | 17.0 °C | 13.8 °C – 20.9 °C | pleasant |
| October | 16.5 °C | 13.5 °C – 20.2 °C | pleasant |
| November | 15.3 °C | 12.9 °C – 18.0 °C | cool |
| December | 14.2 °C | 12.2 °C – 16.5 °C | cool |
Compared with December, the water cools down by 0.9 °C in January. The warmest month: September (17.0 °C). The coldest: April (12.8 °C).
Nearby, in January
- Oregon 10.4 °C · cold
- Washington 9.2 °C · very cold
And right now?
For the temperature measured right now, station by station and to the hour: California: water temperature
Frequently asked questions
What is the sea temperature in January?
California, in January: 13.3 °C on average along the coast, from 11.4 °C in the coolest waters to 15.5 °C in the warmest (average of the years 2011 to 2025).
Can you swim in January?
Where the water is warmest (15.5 °C), it is cool. Swimming is fine if you like cool water: you get used to it after a few minutes, especially in mild weather.
What is the best month for swimming?
The water is warmest in September (17.0 °C on average) and coldest in April (12.8 °C). Where the water is warmest, it goes above 20 °C in these months: July, August, September, October.
What temperature do you need to swim comfortably?
Below 15 °C the water is cold: the cold takes your breath away and tires you quickly. Between 20 °C and 25 °C most people find it pleasant. Below 10 °C it is very cold.
Where do these temperatures come from?
These are averages of the sea surface temperature from 2011 to 2025, computed from NOAA satellite images (OISST, one value about every 50 km), in a 100 km strip along the coasts of the main country: distant territories (overseas, remote islands) are not counted. It is an estimate, not a measurement taken at the beach: lakes and rivers are not included.