San Francisco in September
Find out everything about the water temperature in San Francisco in September. Average, minimum and maximum recorded temperatures as well as daily temperature in September for the last two years. Compare the current month's sea temperature data with other months of the year.
Water temperature in September
Minimum:
58.0 °F
Average:
63.3 °F
Maximum:
66.8 °F
Sea water temperature in San Francisco in September
In the city of San Francisco, the month of September is somewhat too cool for swimming. The minimum recorded temperature during this month was 58.0°F on September 30, 2016, with an average temperature being 63.3°F and a maximum temperature reaching 66.8°F on September 13, 2022.
| Date | 10 years average | 2025 | 2024 |
|---|---|---|---|
| Sep 1 | 63.8°F | 66.0°F | 63.0°F |
| Sep 2 | 63.5°F | 66.6°F | 61.9°F |
| Sep 3 | 63.6°F | 65.9°F | 62.5°F |
| Sep 4 | 63.4°F | 65.4°F | 62.5°F |
| Sep 5 | 63.4°F | 63.4°F | 63.9°F |
| Sep 6 | 63.4°F | 63.4°F | 63.8°F |
| Sep 7 | 63.6°F | 63.4°F | 64.2°F |
| Sep 8 | 63.4°F | 63.3°F | 63.2°F |
| Sep 9 | 64.0°F | 64.4°F | 64.4°F |
| Sep 10 | 64.0°F | 65.1°F | 65.6°F |
| Sep 11 | 63.7°F | 63.6°F | 65.1°F |
| Sep 12 | 63.4°F | 62.3°F | 64.9°F |
| Sep 13 | 63.9°F | 64.7°F | 65.7°F |
| Sep 14 | 63.2°F | 65.1°F | 64.6°F |
| Sep 15 | 63.2°F | 65.1°F | 64.6°F |
| Sep 16 | 62.9°F | 65.2°F | 62.8°F |
| Sep 17 | 63.0°F | 65.7°F | 61.6°F |
| Sep 18 | 63.2°F | 66.0°F | 61.2°F |
| Sep 19 | 63.2°F | 66.8°F | 61.4°F |
| Sep 20 | 63.2°F | 66.0°F | 61.0°F |
| Sep 21 | 63.3°F | 65.0°F | 62.6°F |
| Sep 22 | 63.1°F | 64.7°F | 61.8°F |
| Sep 23 | 63.1°F | 64.8°F | 62.4°F |
| Sep 24 | 63.1°F | 65.4°F | 62.2°F |
| Sep 25 | 63.1°F | 64.7°F | 62.8°F |
| Sep 26 | 63.4°F | 64.1°F | 63.3°F |
| Sep 27 | 63.0°F | 64.1°F | 61.3°F |
| Sep 28 | 63.1°F | 64.5°F | 62.9°F |
| Sep 29 | 62.9°F | 63.7°F | 61.5°F |
| Sep 30 | 62.5°F | 64.7°F | 61.0°F |
In an average year, San Francisco offers no days when the water temperature is warm enough to swim comfortably.
The warmest water in San Francisco was recorded on August 28, 2023, reaching a 67.4°F. While the coldest temperature occurred on March 4, 2023, dipping to 49.3°F. The average readings by season are 53.4°F in Winter, 56.4°F in Spring, 61.2°F in Summer, and 60.9°F in Autumn.
In September, the temperature is higher than August's average of 62.7°F and October's average of 61.4°F.
Popular neighboring cities and resorts
| City | Water temperature* | Distance** |
|---|---|---|
| Oakland |
53.9°F
|
8mi |
| Redwood City |
53.9°F
|
22mi |
| San Jose |
53.6°F
|
42mi |
* current water temperature in this city
** straight line distance from San Francisco