We know this has been a mild winter. After a near normal December, we’ve seen January and February running well above normal in terms of temperatures. The coldest part of winter was around Christmas when blizzard conditions visited the west side of the state near Lake Michigan.
What does this mild weather mean for the Great Lakes? Check out this graph on Ice Cover for Lake Michigan.
RELATED: Great Lakes ice cover has already peaked, and there wasn’t much of it
Ice Coverage on Lake Michigan this year (black line) is well below normal.
Interestingly, February is typically the month with the most amount of ice on the Great Lakes. This makes sense considering the seasons. February brings the coldest water temperatures and August features the warmest lake water temperatures.
Since water cools and warms slower than air, you find the coldest readings towards the end of winter and the warmest readings towards the end of summer.
There have been years where Lake Michigan has become 80% to 90% covered in ice. 1994 is an example, as shown by the red line in the graph. 2002 actually experienced less ice cover than this year so far, shown by the green line. The black line is this year, which shows ice coverage on Lake Michigan peaked at about 22% earlier this month when we had a few days in row below freezing and a couple nights near 0 degrees, but after record high temperatures yesterday, the ice coverage has since dropped back off to less than 10%.
We could do a similar dissection of all 5 Great Lakes. In fact, let’s take a look at this chart from Lake Superior. The historical average maximum amount of ice coverage on the Lake comes right around March 1st at roughly 45% to 50%. On average in Mid-February, we should be running at 40% ice coverage, but instead, the maximum amount of ice coverage this year has stayed below 20% and today it is less than 10%. As of the most recent analysis from yesterday, the entire Great Lakes as a whole are at 6.6% ice coverage, which is significantly below the normal of 40% for this time of year.
Ice Coverage on Lake Superior this year (black) is well below the average for this time of year (red).
As of February 14th, 2023, Ice coverage is 6.6% across the Great Lakes, which is well below the normal of near 40% for mid-February.
Because of this, ice fishing shanties have had to be removed early this year. So, we can’t go ice fishing in a lot of places, but what are the current lake temperatures?
Here is a look at current observed sea surface temperatures (SST) on the Great Lakes (the water temperature at the surface). There is a lot of blue on the map, which indicates single digits Celsius, which equates to 30s and lower-40s in Fahrenheit. The coldest water temperatures are near shore, where you see the darker blues, which indicates readings are closer to the 32-degree Fahrenheit mark. This cold shows up well in the Saginaw Bay.
Great Lakes Water Temperatures are near 32 degrees at the lakeshores and beaches (dark blue).
Because the Lakes are usually covered in ice this time of year, lake effect snow typically becomes less of a concern during late winter. Since there is not much ice this year, though, lake effect must continue to be strongly considered and taken into account when forecasting cold temperatures and snow this month.