San Mateo C water temperature
San Mateo C, Lo Crystal Sp Reservoir near San Mateo, California · River
The current water temperature at San Mateo C is 14.4 °C (as of September 21, 2026, source: USGS).
A river can change temperature within hours — snowmelt, rain or power-plant operations show up immediately. That is why the measured value counts here, not an estimate.
Measurement series & statistics
This measurement series includes 383 data points since July 23, 2026.
Lowest recorded value: 13.7 °C on August 16, 2026 · highest value: 19.4 °C on September 9, 2026.
In September, temperatures have ranged between 13.8 °C and 19.4 °C.
The current value is 2.0 °C below the September average of this series.
Nearby waters
Frequently asked questions
Can you swim at San Mateo C right now?
The current water temperature is 14.4 °C. See live swimming conditions, weather and quality in the BrrChecker app.
How warm is the water at San Mateo C?
Currently 14.4 °C (updated continuously).
How warm is at San Mateo C in September?
In September, the water temperature recently averaged 16.4 °C.
When is the water warmest at San Mateo C?
Across the measurement record, August is on average the warmest month (16.8 °C).
