Frost Dates for 48449 — Lennon, Michigan

Half of springs at Durand Wwtp, MI see their last 32°F night by May 3; only one in ten is past it by April 21, and one in ten still has one after May 19. Planting tender crops after May 9 leaves a 30% risk of a frost on them, after May 14 20%, and after May 19 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 38% of the 172 Michigan stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 11 in half of years, as early as September 29 one year in ten, and holds off past October 25 one year in ten. A hard freeze of 28°F follows 13 days later, around October 24; in spring the one-in-ten date for 28°F is May 8, 11 days before the 32°F one. The freeze-free season lasts 159 days in a typical year, longer than at 51% of the 172 Michigan stations; it reaches 179 days one year in ten and falls short of 139 one year in ten. On average 148 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 13, and return around September 30. Severe cold of 16°F or below comes every winter, usually between November 29 and March 22.

July is the warmest month at Durand Wwtp, MI, averaging 83°F by day and 61°F at night; January is the coldest at 31°F and 15°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 56% of years.

Warmth for growing adds up to 2,661 growing degree days a year (base 50°F), more than at 68% of the 172 Michigan stations. 33% of them (879) have built up by the end of June, and July adds the most, 680. Precipitation totals 33.7 inches a year, most in May (4.1") and least in February (1.5"); May to September bring 52% of it.

The nearest other station, Corunna 2 NE, MI, 7 miles west of Lennon, has a last frost 2 days later (May 5), a first frost 3 days later (October 14), a season 1 day longer.

The first measurable snow (0.1 inch or more) in Lennon usually arrives around November 21, and the last of the season around April 9. Those are the middle dates across the winters of 1991–2020 at Durand Wwtp, MI, 4.8 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 24 days after the last snow.

ZIP 48449 is 5 miles from Durand Wwtp, MI, which stands at 770 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 5 other ZIP codes share the station; its figures are presented in full for 48429 (Durand). The 2023 USDA Plant Hardiness Zone Map lists ZIP 48449 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.