Frost Dates for 49238 — Deerfield, Michigan

Half of springs at Blissfield 1NNE, MI see their last 32°F night by April 29; only one in ten is past it by April 15, and one in ten still has one after May 15. Planting tender crops after May 5 leaves a 30% risk of a frost on them, after May 9 20%, and after May 15 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 13 in half of years, as early as September 30 one year in ten, and holds off past October 26 one year in ten. A hard freeze of 28°F follows 13 days later, around October 26; in spring the one-in-ten date for 28°F is May 2, 13 days before the 32°F one. The freeze-free season lasts 168 days in a typical year, longer than at 76% of the 172 Michigan stations; it reaches 187 days one year in ten and falls short of 147 one year in ten. On average 141 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 9, and return around October 2. Severe cold of 16°F or below comes every winter, usually between December 1 and March 16.

July is the warmest month at Blissfield 1NNE, MI, averaging 83°F by day and 61°F at night; January is the coldest at 32°F and 16°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 41% of years.

Warmth for growing adds up to 2,757 growing degree days a year (base 50°F), more than at 81% of the 172 Michigan stations. 34% of them (940) have built up by the end of June, and July adds the most, 670.

The nearest other station, Dundee, MI, 8 miles northeast of Deerfield, has a last frost 2 days earlier (April 27), a first frost 8 days later (October 21), a season 8 days longer.

The first measurable snow (0.1 inch or more) in Deerfield usually arrives around December 3, and the last of the season around March 14. Those are the middle dates across the winters of 1991–2020 at Tecumseh, MI, 9.9 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 46 days after the last snow.

ZIP 49238 is 6 miles from Blissfield 1NNE, MI, which stands at 690 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 48144 (Lambertville). The 2023 USDA Plant Hardiness Zone Map lists ZIP 49238 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.