As the above chart shows, based on the 30-year average, the lake’s average water temperature should be in the mid-50s. But thanks to scant lake ice cover this past winter, along with a rare March heat wave and warmer-than-average weather since then, the lake began warming earlier than normal, and that warming has kept right on going. Wintertime ice cover on the Great Lakes was the lowest observed since such records began in 1980.
Data shows a long-term warming trend throughout the Great Lakes, which may be related to manmade climate change. According to George Leskevich, a physical research scientist with the Great Lakes Environmental Research Laboratory in Ann Arbor, Mich., there is also a long-term downward trend in Great Lakes wintertime ice cover, although there is considerable year-to-year variability.
Ironically, if the lakes enter the fall with record warm temperatures, it could herald an above-average season for lake effect snow, which occurs when cold, dry air blows across large expanses of comparatively milder waters.