Frost Dates for 54437 — Greenwood, Wisconsin

Half of springs at Owen 1E, WI see their last 32°F night by May 13; only one in ten is past it by April 29, and one in ten still has one after May 29. Planting tender crops after May 19 leaves a 30% risk of a frost on them, after May 23 20%, and after May 29 10%. The 16 days between the even-odds date and the one-in-ten date is wider than at 70% of the 182 Wisconsin stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 26 in half of years, as early as September 12 one year in ten, and holds off past October 10 one year in ten. A hard freeze of 28°F follows 9 days later, around October 5; in spring the one-in-ten date for 28°F is May 17, 12 days before the 32°F one. The freeze-free season lasts 136 days in a typical year, shorter than at 89% of the 182 Wisconsin stations; it reaches 155 days one year in ten and falls short of 116 one year in ten. On average 173 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 12 days longer, to about May 25, and return around September 17. Severe cold of 16°F or below comes every winter, usually between November 11 and April 3.

July is the warmest month at Owen 1E, WI, averaging 79°F by day and 56°F at night; January is the coldest at 21°F and 2°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 86% of years.

Warmth for growing adds up to 2,010 growing degree days a year (base 50°F), fewer than at 86% of the 182 Wisconsin stations. 33% of them (658) have built up by the end of June, and July adds the most, 547. Precipitation totals 34.4 inches a year, most in June (4.8") and least in January (1.1"); May to September bring 61% of it.

The nearest other station, Neillsville 3ESE, WI, 17 miles south of Greenwood and 158 feet lower, has a last frost 3 days earlier (May 10), a first frost 5 days later (October 1), a season 8 days longer.

The first measurable snow (0.1 inch or more) in Greenwood usually arrives around November 7, and the last of the season around April 14. Those are the middle dates across the winters of 1991–2020 at Owen 1E, WI, 12.4 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 29 days after the last snow.

ZIP 54437 is 12 miles from Owen 1E, WI, which stands at 1,238 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 5 other ZIP codes share the station; its figures are presented in full for 54421 (Colby). The 2023 USDA Plant Hardiness Zone Map lists ZIP 54437 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.