Frost Dates for 49715 — Brimley, Michigan

Half of springs at Rudyard 4N, MI see their last 32°F night by May 24; only one in ten is past it by May 8, and one in ten still has one after June 10. Planting tender crops after May 31 leaves a 30% risk of a frost on them, after June 3 20%, and after June 10 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 62% 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 14 one year in ten, and holds off past October 14 one year in ten. A hard freeze of 28°F follows 11 days later, around October 12; in spring the one-in-ten date for 28°F is May 26, 15 days before the 32°F one. The freeze-free season lasts 127 days in a typical year, shorter than at 88% of the 172 Michigan stations; it reaches 149 days one year in ten and falls short of 104 one year in ten. On average 181 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 6, and return around September 17. Severe cold of 16°F or below comes every winter, usually between November 19 and April 4.

July is the warmest month at Rudyard 4N, MI, averaging 79°F by day and 53°F at night; January is the coldest at 25°F and 8°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 28% of years.

Warmth for growing adds up to 1,783 growing degree days a year (base 50°F), fewer than at 88% of the 172 Michigan stations. 29% of them (517) have built up by the end of June, and July adds the most, 496. Precipitation totals 35.9 inches a year, most in October (4.4") and least in February (1.5"); May to September bring 47% of it.

The nearest other station, Sault Ste Marie Sanderson Field, MI, 15 miles east of Brimley, has a last frost 15 days earlier (May 9), a first frost 10 days later (October 11), a season 24 days longer.

The first measurable snow (0.1 inch or more) in Brimley usually arrives around October 27, and the last of the season around April 18. Those are the middle dates across the winters of 1991–2020 at Rudyard 4N, MI, 9 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 36 days after the last snow.

ZIP 49715 is 9 miles from Rudyard 4N, MI, which stands at 753 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 49715 in zone 4b, the band where the coldest night of the year averaged -25 to -20°F (-31.7 to -28.9°C) over 1991–2020; a zone describes winter lows, not frost dates.