Frost Dates for 48463 — Otisville, Michigan

Half of springs at Burton 4N, MI see their last 32°F night by May 8; only one in ten is past it by April 28, and one in ten still has one after May 22. Planting tender crops after May 14 leaves a 30% risk of a frost on them, after May 18 20%, and after May 22 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 80% of the 172 Michigan stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 5 in half of years, as early as September 22 one year in ten, and holds off past October 19 one year in ten. A hard freeze of 28°F follows 14 days later, around October 19; in spring the one-in-ten date for 28°F is May 13, 9 days before the 32°F one. The freeze-free season lasts 148 days in a typical year, shorter than at 66% of the 172 Michigan stations; it reaches 166 days one year in ten and falls short of 130 one year in ten. On average 159 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 20, and return around September 25. Severe cold of 16°F or below comes every winter, usually between November 25 and March 31.

July is the warmest month at Burton 4N, MI, averaging 84°F by day and 58°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 78% of years.

Warmth for growing adds up to 2,488 growing degree days a year (base 50°F), more than at 51% of the 172 Michigan stations. 32% of them (798) have built up by the end of June, and July adds the most, 640.

The nearest other station, Lapeer 2W, MI, 11 miles southeast of Otisville, has a last frost 4 days earlier (May 4), a first frost 8 days later (October 13), a season 13 days longer.

The first measurable snow (0.1 inch or more) in Otisville 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, 8.4 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 48463 is 8 miles from Burton 4N, MI, which stands at 757 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 48423 (Davison). The 2023 USDA Plant Hardiness Zone Map lists ZIP 48463 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.