Frost Dates for 48095 — Washington, Michigan

Half of springs at Richmond 4 NNW, MI see their last 32°F night by May 1; only one in ten is past it by April 18, and one in ten still has one after May 17. Planting tender crops after May 6 leaves a 30% risk of a frost on them, after May 11 20%, and after May 17 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 38% of the 172 Michigan stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 20 in half of years, as early as October 4 one year in ten, and holds off past November 3 one year in ten. A hard freeze of 28°F follows 12 days later, around November 1; in spring the one-in-ten date for 28°F is May 4, 13 days before the 32°F one. The freeze-free season lasts 170 days in a typical year, longer than at 76% of the 172 Michigan stations; it reaches 191 days one year in ten and falls short of 150 one year in ten. On average 143 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 9 days longer, to about May 10, and return around October 6. Severe cold of 16°F or below comes every winter, usually between December 4 and March 16.

July is the warmest month at Richmond 4 NNW, MI, averaging 83°F by day and 62°F at night; January is the coldest at 30°F and 16°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 50% of years.

Warmth for growing adds up to 2,709 growing degree days a year (base 50°F), more than at 74% of the 172 Michigan stations. 33% of them (889) have built up by the end of June, and July adds the most, 699. Precipitation totals 36.1 inches a year, most in July (3.9") and least in February (1.9"); May to September bring 50% of it.

The nearest other station, Pontiac Wwtp, MI, 15 miles southwest of Washington, has a last frost 5 days earlier (April 26), a first frost 2 days later (October 22), a season 7 days longer.

The first measurable snow (0.1 inch or more) in Washington usually arrives around November 22, and the last of the season around April 15. Those are the middle dates across the winters of 1991–2020 at Richmond 4 NNW, MI, 13.5 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 16 days after the last snow.

ZIP 48095 is 14 miles from Richmond 4 NNW, MI, which stands at 765 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 10 other ZIP codes share the station; its figures are presented in full for 48065 (Romeo). The 2023 USDA Plant Hardiness Zone Map lists ZIP 48095 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.