Frost Dates for 49683 — Thompsonville, Michigan

Half of springs at Beulah 7SSW, MI see their last 32°F night by May 7; only one in ten is past it by April 23, and one in ten still has one after May 25. Planting tender crops after May 15 leaves a 30% risk of a frost on them, after May 20 20%, and after May 25 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 81% 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 4 one year in ten. A hard freeze of 28°F follows 14 days later, around November 3; in spring the one-in-ten date for 28°F is May 12, 13 days before the 32°F one. The freeze-free season lasts 163 days in a typical year, longer than at 62% of the 172 Michigan stations; it reaches 185 days one year in ten and falls short of 141 one year in ten. On average 146 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 15 days longer, to about May 22, and return around October 5. Severe cold of 16°F or below comes every winter, usually between December 6 and March 24.

July is the warmest month at Beulah 7SSW, MI, averaging 80°F by day and 59°F at night; January is the coldest at 29°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 68% of years.

Warmth for growing adds up to 2,321 growing degree days a year (base 50°F), fewer than at 55% of the 172 Michigan stations. 30% of them (707) have built up by the end of June, and July adds the most, 593. Precipitation totals 36.4 inches a year, most in October (4.6") and least in February (1.8"); May to September bring 45% of it.

The nearest other station, Frankfort 2NE, MI, 16 miles northwest of Thompsonville and 175 feet higher, has a last frost 5 days earlier (May 2), a first frost 6 days later (October 26), a season 12 days longer.

The first measurable snow (0.1 inch or more) in Thompsonville usually arrives around November 9, and the last of the season around April 15. Those are the middle dates across the winters of 1991–2020 at Beulah 7SSW, MI, 9.7 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 22 days after the last snow.

ZIP 49683 is 10 miles from Beulah 7SSW, MI, which stands at 773 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 49614 (Bear Lake). The 2023 USDA Plant Hardiness Zone Map lists ZIP 49683 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.