Frost Dates for 48768 — Vassar, Michigan

Half of springs at Vassar, MI see their last 32°F night by May 9; only one in ten is past it by April 26, and one in ten still has one after May 24. Planting tender crops after May 16 leaves a 30% risk of a frost on them, after May 19 20%, and after May 24 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 55% of the 172 Michigan stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 7 in half of years, as early as September 24 one year in ten, and holds off past October 21 one year in ten. A hard freeze of 28°F follows 14 days later, around October 21; in spring the one-in-ten date for 28°F is May 15, 9 days before the 32°F one. The freeze-free season lasts 150 days in a typical year, shorter than at 65% of the 172 Michigan stations; it reaches 169 days one year in ten and falls short of 130 one year in ten. On average 160 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 12 days longer, to about May 21, and return around September 27. Severe cold of 16°F or below comes every winter, usually between November 25 and March 27.

July is the warmest month at Vassar, MI, averaging 82°F by day and 57°F at night; January is the coldest at 30°F and 12°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 78% of years.

Warmth for growing adds up to 2,371 growing degree days a year (base 50°F), fewer than at 55% of the 172 Michigan stations. 32% of them (760) have built up by the end of June, and July adds the most, 603. Precipitation totals 34.4 inches a year, most in July (4.1") and least in February (1.5"); May to September bring 52% of it.

The nearest other station, Frankenmuth 1SE, MI, 8 miles southwest of Vassar, has a last frost 6 days earlier (May 3), a first frost 5 days later (October 12), a season 11 days longer.

The first measurable snow (0.1 inch or more) in Vassar usually arrives around November 17, and the last of the season around April 7. Those are the middle dates across the winters of 1991–2020 at Millington 3 SE, MI, 7.8 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 32 days after the last snow.

ZIP 48768 is under a mile from Vassar, MI, which stands at 630 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 48768 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.