Sf Bay A San Mateo Bridge, Foster City, California · Sea/Coast
The current water temperature at Sf Bay A San Mateo Bridge is 20.3 °C (as of September 21, 2026, source: USGS).
The sea lags the air by weeks: the warmest water often arrives after the warmest days. Measured buoy values show this honestly.
This measurement series includes 383 data points since July 23, 2026.
Lowest recorded value: 20.2 °C on September 1, 2026 · highest value: 22.9 °C on August 7, 2026.
In September, temperatures have ranged between 20.2 °C and 21.6 °C.
The current value is 0.3 °C below the September average of this series.
Can you swim at Sf Bay A San Mateo Bridge right now?
The current water temperature is 20.3 °C. See live swimming conditions, weather and quality in the BrrChecker app.
How warm is the water at Sf Bay A San Mateo Bridge?
Currently 20.3 °C (updated continuously).
How warm is at Sf Bay A San Mateo Bridge in September?
In September, the water temperature recently averaged 20.6 °C.
When is the water warmest at Sf Bay A San Mateo Bridge?
Across the measurement record, August is on average the warmest month (21.8 °C).