Frost Dates for 49325 — Freeport, Michigan

Half of springs at Hastings, MI see their last 32°F night by May 3; only one in ten is past it by April 20, and one in ten still has one after May 22. Planting tender crops after May 11 leaves a 30% risk of a frost on them, after May 15 20%, and after May 22 10%. The 19 days between the even-odds date and the one-in-ten date is wider than at 93% of the 172 Michigan stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 12 in half of years, as early as September 29 one year in ten, and holds off past October 28 one year in ten. A hard freeze of 28°F follows 14 days later, around October 26; in spring the one-in-ten date for 28°F is May 11, 11 days before the 32°F one. The freeze-free season lasts 158 days in a typical year, shorter than at 50% of the 172 Michigan stations; it reaches 178 days one year in ten and falls short of 137 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 14 days longer, to about May 17, and return around October 1. Severe cold of 16°F or below comes every winter, usually between December 2 and March 22.

July is the warmest month at Hastings, MI, averaging 82°F by day and 59°F at night; January is the coldest at 31°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 60% of years.

Warmth for growing adds up to 2,536 growing degree days a year (base 50°F), more than at 55% of the 172 Michigan stations. 33% of them (830) have built up by the end of June, and July adds the most, 634. Precipitation totals 39.5 inches a year, most in May (4.4") and least in February (2.1"); May to September bring 48% of it.

The nearest other station, Nwsfo Grand Rapids, MI, 15 miles northwest of Freeport, has a last frost 3 days earlier (April 30), a first frost 2 days later (October 14), a season 9 days longer.

The first measurable snow (0.1 inch or more) in Freeport usually arrives around November 10, and the last of the season around April 13. Those are the middle dates across the winters of 1991–2020 at Hastings, MI, 8.5 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 20 days after the last snow.

ZIP 49325 is 9 miles from Hastings, MI, which stands at 821 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 49058 (Hastings). The 2023 USDA Plant Hardiness Zone Map lists ZIP 49325 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.