Frost Dates for 54208 — Denmark, Wisconsin

Half of springs at Denmark Wwtp, WI see their last 32°F night by May 6; only one in ten is past it by April 22, and one in ten still has one after May 20. Planting tender crops after May 11 leaves a 30% risk of a frost on them, after May 15 20%, and after May 20 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 58% of the 182 Wisconsin stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 12 in half of years, as early as September 30 one year in ten, and holds off past October 27 one year in ten. A hard freeze of 28°F follows 14 days later, around October 26; in spring the one-in-ten date for 28°F is May 9, 11 days before the 32°F one. The freeze-free season lasts 158 days in a typical year, longer than at 56% of the 182 Wisconsin stations; it reaches 179 days one year in ten and falls short of 139 one year in ten. On average 156 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 18, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 24 and March 25.

July is the warmest month at Denmark Wwtp, WI, averaging 80°F by day and 59°F at night; January is the coldest at 25°F and 10°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 68% of years.

Warmth for growing adds up to 2,259 growing degree days a year (base 50°F), fewer than at 70% of the 182 Wisconsin stations. 30% of them (679) have built up by the end of June, and July adds the most, 603. Precipitation totals 30.0 inches a year, most in June (3.9") and least in February (1.0"); May to September bring 56% of it.

The nearest other station, Kewaunee, WI, 16 miles northeast of Denmark and 218 feet lower, has a last frost 5 days earlier (May 1), a first frost 6 days later (October 18), a season 10 days longer.

The first measurable snow (0.1 inch or more) in Denmark usually arrives around December 1, and the last of the season around April 6. Those are the middle dates across the winters of 1991–2020 at Kewaunee, WI, 16.1 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 30 days after the last snow.

ZIP 54208 is under a mile from Denmark Wwtp, WI, which stands at 811 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 54208 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.