Frost Dates for 48647 — Mio, Michigan

Half of springs at Mio Wwtp, MI see their last 32°F night by May 20; only one in ten is past it by May 2, and one in ten still has one after June 2. Planting tender crops after May 27 leaves a 30% risk of a frost on them, after May 30 20%, and after June 2 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 95% of the 172 Michigan stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 1 in half of years, as early as September 16 one year in ten, and holds off past October 14 one year in ten. A hard freeze of 28°F follows 13 days later, around October 14; in spring the one-in-ten date for 28°F is May 23, 10 days before the 32°F one. The freeze-free season lasts 133 days in a typical year, shorter than at 81% of the 172 Michigan stations; it reaches 154 days one year in ten and falls short of 112 one year in ten. On average 180 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 June 2, and return around September 19. Severe cold of 16°F or below comes every winter, usually between November 22 and April 3.

July is the warmest month at Mio Wwtp, MI, averaging 81°F by day and 56°F at night; January is the coldest at 28°F and 11°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 89% of years and June still brings one in 15% of years.

Warmth for growing adds up to 2,123 growing degree days a year (base 50°F), fewer than at 70% of the 172 Michigan stations. 32% of them (678) have built up by the end of June, and July adds the most, 566. Precipitation totals 32.0 inches a year, most in August (3.8") and least in February (1.4"); May to September bring 52% of it.

The nearest other station, Lupton 1S, MI, 17 miles south of Mio, has a last frost 1 day later (May 21), a first frost 2 days earlier (September 29), a season 4 days shorter.

The first measurable snow (0.1 inch or more) in Mio usually arrives around November 23, and the last of the season around April 5. Those are the middle dates across the winters of 1991–2020 at Lupton 1S, MI, 16.6 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 45 days after the last snow.

ZIP 48647 is under a mile from Mio Wwtp, MI, which stands at 1,037 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 48647 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.