Frost Dates for 48023 — Ira, Michigan

Half of springs at Algonac Wwtp, MI see their last 32°F night by May 3; only one in ten is past it by April 20, and one in ten still has one after May 23. Planting tender crops after May 11 leaves a 30% risk of a frost on them, after May 16 20%, and after May 23 10%. The 20 days between the even-odds date and the one-in-ten date is wider than at 95% of the 172 Michigan stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 18 in half of years, as early as October 4 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 13 days later, around October 31; in spring the one-in-ten date for 28°F is May 8, 15 days before the 32°F one. The freeze-free season lasts 167 days in a typical year, longer than at 73% of the 172 Michigan stations; it reaches 185 days one year in ten and falls short of 141 one year in ten. On average 137 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 15 days longer, to about May 18, and return around October 6. Severe cold of 16°F or below comes every winter, usually between December 5 and March 19.

July is the warmest month at Algonac Wwtp, MI, averaging 85°F by day and 60°F at night; January is the coldest at 33°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 54% of years.

Warmth for growing adds up to 2,736 growing degree days a year (base 50°F), more than at 78% of the 172 Michigan stations. 30% of them (832) have built up by the end of June, and July adds the most, 699.

The nearest other station, Mt Clemens Ang Base, MI, 10 miles southwest of Ira, has a last frost 3 days earlier (April 30), a first frost 6 days later (October 24), a season 7 days longer.

The first measurable snow (0.1 inch or more) in Ira usually arrives around November 28, and the last of the season around April 9. Those are the middle dates across the winters of 1991–2020 at Mt Clemens Ang Base, MI, 9.6 miles away: half of years saw snow earlier, half later. Snow fell in 95% of those winters. The last 32°F night of spring typically comes 24 days after the last snow.

ZIP 48023 is 8 miles from Algonac Wwtp, MI, which stands at 580 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 48001 (Algonac). The 2023 USDA Plant Hardiness Zone Map lists ZIP 48023 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.