While Great Lakes water levels were up in early May from the previous month, the U.S. Army Corps of Engineers says they are all lower than their 2024 averages, by as much as 8 inches.
“The forecast May 9th water levels are above levels from a month ago by 2 to 7 inches on all lakes as the lakes continue their seasonal rise,” the U.S. Army Corps of Engineers’ Weekly Great Lakes Water Level Update said. “However, the projected May 9th levels are below water levels from a year ago by 1 to 8 inches depending on the lake.”
The 2024-25 ice season saw more normal ice coverage, the Corps said. April marked the start of the Great Lakes’ seasonal rise as ice melted.
“In the spring, the ice and snow melts and rainfall become abundant. Water levels will rise through the summer. Lake levels will generally change 1-2 feet from season to season,” Michigan’s Department of Environment, Great Lakes and Energy said.
Lake Superior and Lake Ontario both were up 7 inches from April, the Corps said. Both lakes were down slightly from May 2024, and 4 inches from the long-term May average.
The water level for Lake Michigan and Lake Huron (measured as one), was 578.61 feet, up 4 inches from April, but down 6 inches from the May average — and 8 inches from May 2024.
Lakes St. Clair and Erie were 4 and 5 inches above their long-term May averages, but down 6 inches from May 2024.
The Corps said precipitation in April was above average for the Great Lakes basin, with the Lake Superior basin at 163% of average, Lake Ontario basin received 120% of average, and the Lake Erie basin received 112% of its average as the lakes began their seasonal rises.
Over the past 12 months, total precipitation has been near the long-term average, ranging from 93% to 103% of average, the Corps said.
The updated Great Lakes water levels 6-month forecast predicts that Lakes Superior, Michigan-Huron, and St. Clair will continue to rise in May, while Lakes Erie and Ontario will likely reach their seasonal peak in the next month or two.
Officials forecast the seasonal rise to continue into June for Lake Superior, Lake Michigan and Lake Huron, the Corps said.
Here’s more on the Great Lakes’ water levels:
What are Great Lakes’ water levels?
As of May 9, 2025, the U.S. Army Corps of Engineers update, recorded the water levels for each lake, here are the levels:
Lake Michigan and Lake Huron are recorded as one, because their water levels rise and fall together — they are “connected through the Straits of Mackinac,” Wisconsin Sea Grant said.
What are the records highs, lows for the lakes?
Great Lakes high and low water level records (mean level), from 1918-2023.
How did water levels deviate from average since April?
All of the lakes saw lower average water levels compared to May 9, 2024, here are the differences:
Here are differences from the long-term monthly averages for May:
Why do water levels change in the Great Lakes?
The variability of Great Lakes water levels is necessary and normal, according to EGLE, though high levels can pose issues for waterfront communities.
There are several factors that influence the water levels among the lakes — so much so, water levels are subject to change within hours.
Some factors include the changing seasons (variable weather) precipitation, evaporation, strong winds, seiches, and flood control.
Are the Great Lakes’ water levels predicted to rise?
Yes, officials forecast most of the great lakes to have higher water level by June 9, 2025. Here the projections for the lakes:
Contact Sarah Moore @ smoore@lsj.com
This article originally appeared on Lansing State Journal: Great Lakes water levels are rising. Where do they stand for May?
Reporting by Sarah Moore, Lansing State Journal / Lansing State Journal
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