Great Lakes Ice Cover
The Great Lakes are essentially ice-free: NOAA GLERL's daily ice-cover record for the 2026–27 winter starts when ice forms, usually in late November or December (as of 10 November 2026). Last winter (2025–26), total ice cover peaked at 58.3% on 9 February 2026, above the 1973–2026 average peak of 52.1%.
Last winter (2025–26): peak ice cover by lake
| Lake | Peak | Date | 1973–2026 average peak | Compared with average |
|---|---|---|---|---|
| All five Great Lakes | 58.3% | 9 February 2026 | 52.1% | above |
| Lake Superior | 62.5% | 2 March 2026 | 59.6% | near |
| Lake Michigan | 36.7% | 31 January 2026 | 38.9% | near |
| Lake Huron | 78.5% | 2 March 2026 | 63.4% | above |
| Lake Erie | 96.0% | 5 February 2026 | 80.5% | above |
| Lake Ontario | 41.9% | 9 February 2026 | 29.1% | above |
Yearly peak, last 10 winters
| Winter | All lakes | Sup. | Mich. | Huron | Erie | Ont. |
|---|---|---|---|---|---|---|
| 2025–26 | 58.3% | 62.5% | 36.7% | 78.5% | 96.0% | 41.9% |
| 2024–25 | 52.2% | 45.6% | 33.5% | 71.1% | 95.8% | 26.1% |
| 2023–24 | 16.0% | 12.0% | 18.3% | 22.6% | 35.7% | 5.3% |
| 2022–23 | 21.6% | 19.8% | 21.5% | 34.4% | 40.2% | 16.4% |
| 2021–22 | 56.1% | 79.5% | 37.5% | 67.2% | 93.8% | 29.4% |
| 2020–21 | 45.8% | 50.6% | 33.3% | 48.3% | 85.7% | 20.6% |
| 2019–20 | 19.5% | 22.6% | 17.2% | 32.1% | 15.9% | 10.7% |
| 2018–19 | 80.9% | 94.9% | 55.8% | 95.7% | 94.3% | 39.8% |
| 2017–18 | 69.0% | 77.2% | 51.3% | 81.4% | 95.1% | 24.7% |
| 2016–17 | 19.4% | 18.7% | 18.2% | 35.4% | 35.5% | 5.8% |
Record since 1973 for all lakes: 94.7% (winter 1978–79); lowest 11.8% (2001–02).
How last winter went
| Date | All lakes | Erie | Superior |
|---|---|---|---|
| 1 Dec 2025 | 0.2% | 0.0% | 0.3% |
| 15 Dec 2025 | 5.6% | 12.8% | 2.6% |
| 1 Jan 2026 | 9.2% | 18.2% | 2.5% |
| 15 Jan 2026 | 11.5% | 13.3% | 5.8% |
| 1 Feb 2026 | 54.6% | 95.2% | 47.3% |
| 15 Feb 2026 | 51.6% | 92.5% | 48.9% |
| 1 Mar 2026 | 50.2% | 74.2% | 56.0% |
| 15 Mar 2026 | 20.9% | 12.0% | 24.4% |
| 1 Apr 2026 | 12.0% | 1.2% | 13.6% |
| 15 Apr 2026 | 4.1% | 0.1% | 4.3% |
| 1 May 2026 | 0.4% | 0.0% | 1.2% |
| 15 May 2026 | 0.0% | 0.0% | 0.0% |
First day in GLERL's file: 29 November 2025; last: 16 May 2026.
Why ice cover matters
- Lake-effect snow: open water feeds lake-effect snow downwind (Buffalo, Erie, western Michigan). Once a lake freezes over, that snow largely stops.
- Shipping: the Soo Locks close each winter (mid-January to late March) and icebreakers keep lanes open.
- Water and shorelines: ice cover cuts evaporation and shields shores from winter storms.
- Safety: lake ice is never uniform. Ice shelves and pressure ridges along the shore can break without warning; stay off unless local authorities say otherwise. Advice: NWS winter safety.
What this page shows, and what it misses
The share of each lake's surface covered by ice, averaged over the lake, from NOAA GLERL's daily files (the current winter is read every 6 hours from 15 November to 31 May). Ice concentration is from US National Ice Center and Canadian Ice Service charts, so it says how much water is covered, not how thick or safe the ice is. Bays and harbors can be frozen while the lake average is near zero. Long-term averages and peaks are from GLERL's 1973–2026 record (winters named by their January).
Ice cover: NOAA Great Lakes Environmental Research Laboratory (GLERL), from US National Ice Center and Canadian Ice Service ice analyses. US Government work, public domain.