Lake Superior water temperature
Lake Superior, Grand Marais, Lake Superior · Lake
The current water temperature at Lake Superior is 11.6 °C (as of September 20, 2026, source: NOAA CO-OPS).
Lakes stratify in summer: bathing-warm on top, markedly colder a few metres down. Measurements are taken at the surface — right where you swim.
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Water quality
Official EPA rating: excellentMeasurement series & statistics
This measurement series includes 1175 data points since July 23, 2026.
Lowest recorded value: 8.7 °C on July 23, 2026 · highest value: 12.6 °C on September 9, 2026.
In September, temperatures have ranged between 11.6 °C and 12.6 °C.
The current value is 0.4 °C below the September average of this series.
Nearby waters
More measuring points: Lake Superior
Frequently asked questions
Can you swim at Lake Superior right now?
The current water temperature is 11.6 °C. See live swimming conditions, weather and quality in the BrrChecker app.
How warm is the water at Lake Superior?
Currently 11.6 °C (updated continuously).
How warm is at Lake Superior in September?
In September, the water temperature recently averaged 12.0 °C.
When is the water warmest at Lake Superior?
Across the measurement record, September is on average the warmest month (12.0 °C).
How is the water quality at Lake Superior?
The official classification is: excellent.
