Rio Grande, Mercedes, Texas · River
The current water temperature at Rio Grande is 31.6 °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.
This measurement series includes 153 data points since July 23, 2026.
Lowest recorded value: 30.1 °C on July 24, 2026 · highest value: 32.7 °C on August 1, 2026.
In September, temperatures have ranged between 30.8 °C and 32.2 °C.
The current value is 0.1 °C above the September average of this series.
Can you swim at Rio Grande right now?
The current water temperature is 31.6 °C. See live swimming conditions, weather and quality in the BrrChecker app.
How warm is the water at Rio Grande?
Currently 31.6 °C (updated continuously).
How warm is at Rio Grande in September?
In September, the water temperature recently averaged 31.5 °C.
When is the water warmest at Rio Grande?
Across the measurement record, September is on average the warmest month (31.5 °C).