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Is Lake Superior cold?
The latest NASA JPL satellite analysis, dated November 3, 2026, gives 48°F (8.7°C) at the nearest water pixel. That is extremely cold water.
Below 50°F. Cold shock and rapid loss of muscle control are serious risks; below 40°F water is painfully cold. Temperature is only one factor: check rip current and surf alerts, and swim near lifeguards.
How cold is too cold to swim?Water temperature through the year
Average water temperature by month, satellite 2016–2025. Warmest in August.
Water temperatures around Lake Superior
The 8 stations listed below report 45–56°F. Each reported within the last six hours. These readings describe the listed locations; conditions at individual beaches can differ.
| Station | Water | Type | Updated |
|---|---|---|---|
| Slate Island | 45°F | buoy | 3 h ago |
| MID SUPERIOR- 60 NM North Northeast Hancock, MI | 46°F | buoy | 84 min ago |
| Grand Marais, Lake Superior | 52°F | tide station | 2 h ago |
| East Superior Spotter | 49°F | buoy | 2 h ago |
| WEST SUPERIOR - 30NM NE of Outer Island, WI | 47°F | buoy | 84 min ago |
| Duluth | 56°F | tide station | 2 h ago |
| S.W. Pier, St. Marys River | 54°F | tide station | 2 h ago |
| Little Rapids | 54°F | tide station | 2 h ago |
Average water temperature by month
| Month | Average | Coldest year | Warmest year |
|---|---|---|---|
| January | 37°F | 34°F | 37°F |
| February | 35°F | 31°F | 37°F |
| March | 34°F | 31°F | 36°F |
| April | 35°F | 33°F | 37°F |
| May | 37°F | 36°F | 39°F |
| June | 40°F | 36°F | 44°F |
| July | 49°F | 41°F | 57°F |
| August | 60°F | 55°F | 64°F |
| September | 58°F | 54°F | 63°F |
| October | 51°F | 43°F | 58°F |
| November | 43°F | 40°F | 46°F |
| December | 39°F | 37°F | 40°F |
Water temperatures nearby
Frequently asked questions
Is Lake Superior cold?
The latest NASA JPL satellite analysis, dated November 3, 2026, gives 48°F (8.7°C) at the nearest water pixel. That is extremely cold water. Below 50°F. Cold shock and rapid loss of muscle control are serious risks; below 40°F water is painfully cold. Temperature is only one factor: check rip current and surf alerts, and swim near lifeguards. How cold is too cold?
When is the water warmest at Lake Superior?
Based on satellite data from 2016 to 2025, the water is warmest in August (average 60°F) and coldest in March (average 34°F).
Where does this water temperature come from?
We show NASA JPL’s daily MUR satellite analysis for the nearest water, about 0.0 mi away, when no suitable current in-water sensor is available. Satellite values are typically a degree or two cooler than afternoon readings at the shore. Satellite vs. buoy temperatures.
Sources: NASA JPL MUR satellite analysis; NOAA National Data Buoy Center; forecast and alerts from the National Weather Service. Readings are provisional. All Michigan water temperatures · Methodology