Frost Dates for 49854 — Manistique, Michigan

Half of springs at Manistique Wwtp, MI see their last 32°F night by May 9; only one in ten is past it by April 27, and one in ten still has one after May 23. Planting tender crops after May 15 leaves a 30% risk of a frost on them, after May 19 20%, and after May 23 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 80% of the 172 Michigan stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 10 in half of years, as early as September 27 one year in ten, and holds off past October 27 one year in ten. A hard freeze of 28°F follows 16 days later, around October 26; in spring the one-in-ten date for 28°F is May 10, 13 days before the 32°F one. The freeze-free season lasts 154 days in a typical year, shorter than at 60% of the 172 Michigan stations; it reaches 174 days one year in ten and falls short of 135 one year in ten. On average 167 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 22, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 27 and March 31.

August is the warmest month at Manistique Wwtp, MI, averaging 74°F by day and 56°F at night; January is the coldest at 25°F and 10°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 79% of years.

Warmth for growing adds up to 1,560 growing degree days a year (base 50°F), fewer than at 97% of the 172 Michigan stations. 22% of them (346) have built up by the end of June, and August adds the most, 460.

The nearest other station, Munising, MI, 30 miles northwest of Manistique, has a last frost 7 days later (May 16), a first frost 4 days later (October 14), a season 6 days shorter.

The first measurable snow (0.1 inch or more) in Manistique usually arrives around November 14, and the last of the season around April 9. Those are the middle dates across the winters of 1991–2020 at Manistique Wwtp, 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 30 days after the last snow.

ZIP 49854 is 8 miles from Manistique Wwtp, MI, which stands at 600 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 49854 in zone 5a, the band where the coldest night of the year averaged -20 to -15°F (-28.9 to -26.1°C) over 1991–2020; a zone describes winter lows, not frost dates.