Frost Dates for 49421 — Hesperia, Michigan

Half of springs at Hesperia 4 WNW, MI see their last 32°F night by May 17; only one in ten is past it by April 30, and one in ten still has one after June 1. Planting tender crops after May 24 leaves a 30% risk of a frost on them, after May 28 20%, and after June 1 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 1 in half of years, as early as September 14 one year in ten, and holds off past October 13 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 23, 9 days before the 32°F one. The freeze-free season lasts 137 days in a typical year, shorter than at 76% of the 172 Michigan stations; it reaches 158 days one year in ten and falls short of 113 one year in ten. On average 166 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 30, and return around September 19. Severe cold of 16°F or below comes every winter, usually between November 25 and March 31.

July is the warmest month at Hesperia 4 WNW, MI, averaging 82°F by day and 56°F at night; January is the coldest at 31°F and 14°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 12% of years.

Warmth for growing adds up to 2,261 growing degree days a year (base 50°F), fewer than at 60% of the 172 Michigan stations. 32% of them (720) have built up by the end of June, and July adds the most, 581. Precipitation totals 36.0 inches a year, most in October (4.3") and least in February (1.6"); May to September bring 46% of it.

The nearest other station, Fremont 4 WSW, MI, 11 miles south of Hesperia, has a last frost 9 days earlier (May 8), a first frost 10 days later (October 11), a season 18 days longer.

The first measurable snow (0.1 inch or more) in Hesperia usually arrives around November 16, and the last of the season around March 31. Those are the middle dates across the winters of 1991–2020 at Hesperia 4 WNW, MI, 1 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 47 days after the last snow.

ZIP 49421 is 1 mile from Hesperia 4 WNW, MI, which stands at 780 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 49421 in zone 5b, the band where the coldest night of the year averaged -15 to -10°F (-26.1 to -23.3°C) over 1991–2020; a zone describes winter lows, not frost dates.