San Francisco Bay water temperature
San Francisco Bay, Second Mallard · Sea/Coast
The current water temperature at San Francisco Bay is 20.4 °C (as of September 20, 2026, source: NOAA NERRS SWMP).
The sea lags the air by weeks: the warmest water often arrives after the warmest days. Measured buoy values show this honestly.
Measurement series & statistics
This measurement series includes 68 data points since September 1, 2026.
Lowest recorded value: 18.4 °C on September 8, 2026 · highest value: 21.8 °C on September 9, 2026.
In September, temperatures have ranged between 18.4 °C and 21.8 °C.
The current value is 0.4 °C above the September average of this series.
Nearby waters
More measuring points: San Francisco Bay
Frequently asked questions
Can you swim at San Francisco Bay right now?
The current water temperature is 20.4 °C. See live swimming conditions, weather and quality in the BrrChecker app.
How warm is the water at San Francisco Bay?
Currently 20.4 °C (updated continuously).
How warm is at San Francisco Bay in September?
In September, the water temperature recently averaged 20.0 °C.
