Frost Dates for 53004 — Belgium, Wisconsin

Half of springs at Belgium Wwtp, WI see their last 32°F night by May 5; only one in ten is past it by April 20, and one in ten still has one after May 22. Planting tender crops after May 13 leaves a 30% risk of a frost on them, after May 17 20%, and after May 22 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 90% 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 27 one year in ten, and holds off past October 27 one year in ten. A hard freeze of 28°F follows 13 days later, around October 25; in spring the one-in-ten date for 28°F is May 9, 13 days before the 32°F one. The freeze-free season lasts 159 days in a typical year, longer than at 59% of the 182 Wisconsin stations; it reaches 182 days one year in ten and falls short of 138 one year in ten. On average 154 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 14 days longer, to about May 19, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 23 and March 19.

July is the warmest month at Belgium Wwtp, WI, averaging 80°F by day and 60°F at night; January is the coldest at 27°F and 11°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 63% of years.

Warmth for growing adds up to 2,199 growing degree days a year (base 50°F), fewer than at 76% of the 182 Wisconsin stations. 27% of them (599) have built up by the end of June, and July adds the most, 604.

The nearest other station, Port Washington, WI, 7 miles south of Belgium, has a last frost 8 days earlier (April 27), a first frost 10 days later (October 22), a season 17 days longer.

The first measurable snow (0.1 inch or more) in Belgium usually arrives around December 2, and the last of the season around March 25. Those are the middle dates across the winters of 1991–2020 at Port Washington, WI, 7.2 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 41 days after the last snow.

ZIP 53004 is 1 mile from Belgium Wwtp, WI, which stands at 731 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 53021 (Fredonia). The 2023 USDA Plant Hardiness Zone Map lists ZIP 53004 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.