San Mateo C below Lo Crystal Sp Reservoir near San Mateo, California water temperature

San Mateo C below Lo Crystal Sp Reservoir near San Mateo, California · River

The current water temperature at San Mateo C below Lo Crystal Sp Reservoir near San Mateo is 14.5 °C (as of September 1, 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.

14.5 °C

Measured: September 1, 2026 · continuously updated

💧 Water 14.5° · ☀️ Air 18.0° · high today 19.7°

Temperature trend of recent weeks

San Mateo C below Lo Crystal Sp Reservoir near San Mateo, California — Photo: Calbookaddict (talk) · CC BY 3.0 · Wikimedia Commons

Measurement series & statistics

This measurement series includes 446 data points since July 8, 2026.

Lowest recorded value: 13.6 °C on July 10, 2026 · highest value: 19.2 °C on August 27, 2026.

Nearby waters

Pilarcitos C below Stone Dam near Hillsborough, California · 3.7 km away15.2 °C Pacific, Half Moon Bay · 10.3 km away15.4 °C Sf Bay A San Mateo Bridge near Foster City, California · 11.3 km away20.3 °C South San Francisco Bay at Dumbarton Bridge, California · 21.2 km away20.9 °C Pacific, Alameda · 27.4 km away19.5 °C

Frequently asked questions

Can you swim at San Mateo C below Lo Crystal Sp Reservoir near San Mateo right now?
The current water temperature is 14.5 °C. See live swimming conditions, weather and quality in the BrrChecker app.

How warm is the water at San Mateo C below Lo Crystal Sp Reservoir near San Mateo?
Currently 14.5 °C (updated continuously).

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