Frost Dates for 49301 — Ada, Michigan

Half of springs at Grand Rapids, MI see their last 32°F night by April 29; only one in ten is past it by April 14, and one in ten still has one after May 15. Planting tender crops after May 4 leaves a 30% risk of a frost on them, after May 8 20%, and after May 15 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 2 one year in ten. A hard freeze of 28°F follows 13 days later, around November 2; in spring the one-in-ten date for 28°F is May 2, 13 days before the 32°F one. The freeze-free season lasts 174 days in a typical year, longer than at 85% of the 172 Michigan stations; it reaches 195 days one year in ten and falls short of 151 one year in ten. On average 133 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 8 days longer, to about May 7, and return around October 7. Severe cold of 16°F or below comes every winter, usually between December 7 and March 17.

July is the warmest month at Grand Rapids, MI, averaging 83°F by day and 63°F at night; January is the coldest at 31°F and 19°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 41% of years.

Warmth for growing adds up to 2,888 growing degree days a year (base 50°F), more than at 89% of the 172 Michigan stations. 33% of them (967) have built up by the end of June, and July adds the most, 707. Precipitation totals 39.4 inches a year, most in April (4.0") and least in February (2.1"); May to September bring 48% of it.

The nearest other station, Nwsfo Grand Rapids, MI, 6 miles southwest of Ada, has a last frost 1 day later (April 30), a first frost 6 days earlier (October 14), a season 7 days shorter.

The first measurable snow (0.1 inch or more) in Ada usually arrives around November 9, and the last of the season around April 13. Those are the middle dates across the winters of 1991–2020 at Grand Rapids, MI, 6.4 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 16 days after the last snow.

ZIP 49301 is 6 miles from Grand Rapids, MI, which stands at 778 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 49546 (Grand Rapids). The 2023 USDA Plant Hardiness Zone Map lists ZIP 49301 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.