St Johns River below Marco Lake at Jacksonville, Florida water temperature
St Johns River below Marco Lake at Jacksonville, Florida · River
The current water temperature at St Johns River below Marco Lake at Jacksonville is 29.0 °C (as of September 20, 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 197 data points since July 22, 2026.
Lowest recorded value: 28.4 °C on September 19, 2026 · highest value: 32.9 °C on July 24, 2026.
In September, temperatures have ranged between 28.4 °C and 32.2 °C.
The current value is 0.8 °C below the September average of this series.
Nearby waters
Frequently asked questions
Can you swim at St Johns River below Marco Lake at Jacksonville right now?
The current water temperature is 29.0 °C. See live swimming conditions, weather and quality in the BrrChecker app.
How warm is the water at St Johns River below Marco Lake at Jacksonville?
Currently 29.0 °C (updated continuously).
How warm is at St Johns River below Marco Lake at Jacksonville in September?
In September, the water temperature recently averaged 29.8 °C.
When is the water warmest at St Johns River below Marco Lake at Jacksonville?
Across the measurement record, July is on average the warmest month (31.2 °C).
