Frost Dates for 49235 — Clayton, Michigan

Half of springs at Adrian Lenawee Co Airport, MI see their last 32°F night by April 27; only one in ten is past it by April 13, and one in ten still has one after May 14. Planting tender crops after May 4 leaves a 30% risk of a frost on them, after May 7 20%, and after May 14 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 62% of the 172 Michigan stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 20 in half of years, as early as October 4 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 11 days later, around October 31; in spring the one-in-ten date for 28°F is May 4, 10 days before the 32°F one. The freeze-free season lasts 173 days in a typical year, longer than at 82% of the 172 Michigan stations; it reaches 192 days one year in ten and falls short of 151 one year in ten. On average 132 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 10 days longer, to about May 7, and return around October 6. Severe cold of 16°F or below comes every winter, usually between December 2 and March 15.

July is the warmest month at Adrian Lenawee Co Airport, MI, averaging 84°F by day and 62°F at night; January is the coldest at 32°F and 17°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 38% of years.

Warmth for growing adds up to 2,868 growing degree days a year (base 50°F), more than at 86% of the 172 Michigan stations. 34% of them (971) have built up by the end of June, and July adds the most, 699. Precipitation totals 29.9 inches a year, most in June (3.4") and least in February (1.5"); May to September bring 50% of it.

The nearest other station, Morenci, MI, 9 miles south of Clayton, has a last frost 7 days later (May 4), a first frost 13 days earlier (October 7), a season 17 days shorter.

The first measurable snow (0.1 inch or more) in Clayton usually arrives around November 27, and the last of the season around March 27. Those are the middle dates across the winters of 1991–2020 at Hudson 3 E, MI, 4.5 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 31 days after the last snow.

ZIP 49235 is 7 miles from Adrian Lenawee Co Airport, MI, which stands at 796 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 49235 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.