A sharp drop in temperatures to start the weekend
A cold northeast wind sweeping off Lake Huron is about to bring unexpected frost to many parts of Lower Michigan, catching gardeners and early planters off guard. While Thursday will already feel chilly, the real concern lies in the early hours of Friday, when temperatures may plunge to freezing or below in several communities.
Cold air invades from Lake Huron
Throughout Thursday, a persistent northeast wind—with gusts over 20 mph—will drive cold air inland from Lake Huron, keeping afternoon highs stuck in the 50s°F (10–15°C) range. As the winds calm Thursday night, conditions will become ideal for radiational cooling, setting the stage for frost formation by Friday morning.
Widespread frost forecast for Friday morning
Two of the most reliable weather models agree: frost is coming, though with some variations in intensity and distribution.
According to the more accurate model, nearly all of Lower Michigan is expected to experience frost or even reach the freezing mark—32°F (0°C) for one to two hours. Only Detroit, Monroe, and Adrian may be spared due to urban heat retention. Yet even places like Ann Arbor, Jackson, Kalamazoo, and Grand Rapids are not expected to escape the chill.
Meanwhile, a colder model projects actual freezes from the Thumb region down through Flint, Lansing, Jackson, and Kalamazoo. Southern Michigan would then see more patchy frost, particularly in less urbanized areas.
Sensitive plants at risk of frostbite
If you’ve already planted frost-sensitive vegetables or flowers, be prepared to cover them Thursday evening to protect against a killing frost early Friday. The good news: this may be the final frost of the season for southern Lower Michigan. Forecasts point to above-normal temperatures through at least May 20, giving your garden a chance to recover and thrive.
