Frost Dates for 48427 — Deckerville, Michigan

Half of springs at Sandusky, MI see their last 32°F night by May 2; only one in ten is past it by April 19, and one in ten still has one after May 17. Planting tender crops after May 7 leaves a 30% risk of a frost on them, after May 11 20%, and after May 17 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 16 in half of years, as early as October 1 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 14 days later, around October 30; in spring the one-in-ten date for 28°F is May 6, 11 days before the 32°F one. The freeze-free season lasts 165 days in a typical year, longer than at 69% of the 172 Michigan stations; it reaches 186 days one year in ten and falls short of 145 one year in ten. On average 151 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 12, and return around October 4. Severe cold of 16°F or below comes every winter, usually between December 1 and March 21.

July is the warmest month at Sandusky, MI, averaging 80°F by day and 60°F at night; January is the coldest at 28°F and 15°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 54% of years.

Warmth for growing adds up to 2,396 growing degree days a year (base 50°F), fewer than at 53% of the 172 Michigan stations. 32% of them (760) have built up by the end of June, and July adds the most, 621.

The nearest other station, Lexington Wtp, MI, 20 miles southeast of Deckerville and 152 feet lower, has a last frost 2 days later (May 4), a first frost 8 days later (October 24), a season 6 days longer.

The first measurable snow (0.1 inch or more) in Deckerville usually arrives around November 24, and the last of the season around April 7. Those are the middle dates across the winters of 1991–2020 at Harbor Beach 1 SSE, MI, 21.8 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 25 days after the last snow.

ZIP 48427 is 9 miles from Sandusky, MI, which stands at 774 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 48471 (Sandusky). The 2023 USDA Plant Hardiness Zone Map lists ZIP 48427 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.