Frost Dates for 48441 — Harbor Beach, Michigan

Half of springs at Harbor Beach 1 SSE, 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 8 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 24 in half of years, as early as October 7 one year in ten, and holds off past November 6 one year in ten. A hard freeze of 28°F follows 10 days later, around November 3; in spring the one-in-ten date for 28°F is May 4, 13 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 192 days one year in ten and falls short of 155 one year in ten. On average 146 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 13 days longer, to about May 15, and return around October 11. Severe cold of 16°F or below comes every winter, usually between December 7 and March 17.

July is the warmest month at Harbor Beach 1 SSE, MI, averaging 77°F by day and 60°F at night; January is the coldest at 29°F and 16°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 56% of years.

Warmth for growing adds up to 2,081 growing degree days a year (base 50°F), fewer than at 73% of the 172 Michigan stations. 26% of them (542) have built up by the end of June, and July adds the most, 561. Precipitation totals 34.0 inches a year, most in April (3.6") and least in March (1.9"); May to September bring 47% of it.

The nearest other station, Bad Axe, MI, 15 miles west of Harbor Beach, has a last frost 3 days later (May 5), a first frost 5 days earlier (October 19), a season 10 days shorter.

The first measurable snow (0.1 inch or more) in Harbor Beach 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, 2.8 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 48441 is 3 miles from Harbor Beach 1 SSE, MI, which stands at 595 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 48441 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.