Find the newest Great Lakes water-level report first, followed by earlier weekly snapshots. Reports use official USACE lake-wide daily means and add NOAA GLERL seasonal and historical context. Recent values are provisional and referenced to IGLD 1985. Current U.S. references on this site use Lake America (Lake Ontario), while Canadian, international, historical, and some source materials may continue to use Lake Ontario.
Latest weekly report
Great Lakes Water Levels Weekly Report: August 30–September 6, 2026
Lake St. Clair rose 7 centimeters, Lake Erie rose 5 centimeters, and Lake America (Lake Ontario) rose 2 centimeters. Michigan–Huron was unchanged and Superior eased 1 centimeter. The report includes an original chart, exact elevations, September 4 forecast context, and practical boating implications.
Earlier weekly snapshots
- August 23–30, 2026 weekly report
- August 16–23, 2026 weekly report
- August 10–17, 2026 snapshot
- All Great Lakes Water Levels reports
August 10–17, 2026 snapshot
This weekly snapshot compares official USACE lake-wide daily mean water levels from August 10 through August 17, 2026. All values are provisional and referenced to IGLD 1985.
Great Lakes weekly change
| Lake system | Aug. 10 | Aug. 17 | Change |
|---|---|---|---|
| Lake Superior | 183.51 m | 183.51 m | Unchanged |
| Michigan–Huron | 176.62 m | 176.60 m | −2 cm / −0.8 in |
| Lake St. Clair | 175.34 m | 175.36 m | +2 cm / +0.8 in |
| Lake Erie | 174.42 m | 174.42 m | Unchanged |
| Lake America (Lake Ontario) | 75.32 m | 75.27 m | −5 cm / −2.0 in |
What changed this week
Lake Superior and Lake Erie finished the period at the same daily mean at which they started. Michigan–Huron declined slightly, Lake St. Clair ended slightly higher after day-to-day movement, and Lake America (Lake Ontario) recorded the clearest decline of the five systems.
Changes of a few centimeters are meaningful for tracking lake-wide direction, but local shoreline readings can move much more over short periods because of wind setup, waves, seiches, and harbor geometry. This report should not replace local marine forecasts, navigation charts, or station observations.
Official sources
Current Great Lakes levels · Monthly outlooks