Frost Dates for 48840 — Haslett, Michigan

Half of springs at East Lansing 4 S, MI see their last 32°F night by April 28; only one in ten is past it by April 13, and one in ten still has one after May 16. Planting tender crops after May 4 leaves a 30% risk of a frost on them, after May 9 20%, and after May 16 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 17 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 13 days later, around October 30; in spring the one-in-ten date for 28°F is May 1, 15 days before the 32°F one. The freeze-free season lasts 173 days in a typical year, longer than at 82% of the 172 Michigan stations; it reaches 194 days one year in ten and falls short of 150 one year in ten. On average 145 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 8, and return around October 4. Severe cold of 16°F or below comes every winter, usually between December 4 and March 16.

July is the warmest month at East Lansing 4 S, MI, averaging 83°F by day and 61°F at night; January is the coldest at 32°F and 18°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 39% of years.

Warmth for growing adds up to 2,868 growing degree days a year (base 50°F), more than at 87% of the 172 Michigan stations. 34% of them (964) have built up by the end of June, and July adds the most, 685. Precipitation totals 34.6 inches a year, most in May (4.4") and least in February (1.6"); May to September bring 53% of it.

The nearest other station, Lansing Capital City Airport, MI, 10 miles west of Haslett, has a last frost 3 days later (May 1), a first frost 4 days earlier (October 13), a season 11 days shorter.

The first measurable snow (0.1 inch or more) in Haslett usually arrives around November 25, and the last of the season around March 31. Those are the middle dates across the winters of 1991–2020 at East Lansing 4 S, MI, 7.6 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 28 days after the last snow.

ZIP 48840 is 8 miles from East Lansing 4 S, MI, which stands at 880 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 11 other ZIP codes share the station; its figures are presented in full for 48823 (East Lansing). The 2023 USDA Plant Hardiness Zone Map lists ZIP 48840 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.