Five lakes. One honest number each.
Lake Erie is the bathtub at 77 °F, Lake Superior stays cool at 68, and Lake Ontario runs from 63 to 73 °F depending on the shore. Readings from 113 buoys, tide stations and beach sensors, updated every three hours.
The lakes, right now
Where the sensor sits in the sand
Beach sensors and nearshore buoys, not open-lake averages. Chicago runs its own sensors in the swim zones; Cleveland and Sodus Point report from buoys a few hundred yards out.
Why the same lake can be 73 and 63
Offshore winds push the warm surface layer away from the shore and pull up deep water. Kew Balmy Beach on Lake Ontario reads 63 °F today while Oswego, NY (274), on the same lake, sits at 73. Check the buoy nearest to your beach, not the lake average.
Measured, never modeled
NOAA's National Data Buoy Center runs the offshore buoys, NOAA CO-OPS the tide and water-level stations at the harbors, the Great Lakes Observing System the nearshore monitors, and the Chicago Park District its beach sensors. The EPA rates the beaches. BrrChecker reads them every three hours and shows the time of every measurement.
Erie peaks first and cools first. Michigan and Huron hold their warmth into mid-September on the eastern shores. Superior is for the brave in any month. The app keeps the readings all winter, which is when the cold-plunge crowd shows up.
By lake, with today's reading
Lake Erie 36 stations
Lake Michigan 30 stations
Lake Ontario 21 stations
Lake Huron 13 stations
Lake Superior 13 stations
Which Great Lake is the warmest right now?
Right now the warmest measured value comes from Lake Erie (Toledo) at 77 °F. Erie is usually the warmest of the five (it is the shallowest), Superior the coldest.
Why is Lake Superior so cold?
It is the largest and deepest of the Great Lakes — a huge heat sink that barely warms even in high summer. Many buoys stay below 20°C all year.
How fresh are these values?
The NOAA buoys report continuously; this page shows the freshest buoy per lake with its measurement time, plus a 7-day trend.
Check first, then swim.
Every Great Lakes station with history, BrrScore and alerts, free in the app.
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