San Francisco Bay A Ne Shore Alcatraz Island, California water temperature
San Francisco Bay A Ne Shore Alcatraz Island, California · Sea/Coast
The current water temperature at San Francisco Bay A Ne Shore Alcatraz Island is 18.3 °C (as of September 20, 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.
Measurement series & statistics
This measurement series includes 317 data points since July 22, 2026.
Lowest recorded value: 15.4 °C on July 30, 2026 · highest value: 19.4 °C on July 28, 2026.
In September, temperatures have ranged between 15.9 °C and 18.3 °C.
The current value is 1.1 °C above the September average of this series.
Nearby waters
Frequently asked questions
Can you swim at San Francisco Bay A Ne Shore Alcatraz Island right now?
The current water temperature is 18.3 °C. See live swimming conditions, weather and quality in the BrrChecker app.
How warm is the water at San Francisco Bay A Ne Shore Alcatraz Island?
Currently 18.3 °C (updated continuously).
How warm is at San Francisco Bay A Ne Shore Alcatraz Island in September?
In September, the water temperature recently averaged 17.2 °C.
When is the water warmest at San Francisco Bay A Ne Shore Alcatraz Island?
Across the measurement record, August is on average the warmest month (17.5 °C).
