Frost Dates for 49765 — Onaway, Michigan

Half of springs at Onaway 4N, MI see their last 32°F night by May 22; only one in ten is past it by May 3, 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 11 days between the even-odds date and the one-in-ten date is the narrowest of the 172 Michigan stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 2 in half of years, as early as September 16 one year in ten, and holds off past October 16 one year in ten. A hard freeze of 28°F follows 14 days later, around October 16; in spring the one-in-ten date for 28°F is May 24, 9 days before the 32°F one. The freeze-free season lasts 135 days in a typical year, shorter than at 78% of the 172 Michigan stations; it reaches 156 days one year in ten and falls short of 112 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 11 days longer, to about June 2, and return around September 19. Severe cold of 16°F or below comes every winter, usually between November 24 and April 3.

July is the warmest month at Onaway 4N, MI, averaging 80°F by day and 56°F at night; January is the coldest at 27°F and 12°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 14% of years.

Warmth for growing adds up to 2,106 growing degree days a year (base 50°F), fewer than at 72% of the 172 Michigan stations. 30% of them (633) have built up by the end of June, and July adds the most, 559. Precipitation totals 31.9 inches a year, most in October (3.5") and least in February (1.5"); May to September bring 49% of it.

The nearest other station, Vanderbilt 11ENE, MI, 16 miles southwest of Onaway and 160 feet higher, has a last frost 16 days later (June 7), a first frost 18 days earlier (September 14), a season 40 days shorter.

The first measurable snow (0.1 inch or more) in Onaway usually arrives around November 5, and the last of the season around April 13. Those are the middle dates across the winters of 1991–2020 at Onaway 4N, MI, 4 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 39 days after the last snow.

ZIP 49765 is 4 miles from Onaway 4N, MI, which stands at 745 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 49765 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.