Frost Dates for 54661 — Trempealeau, Wisconsin

Half of springs at Trempealeau Dam 6, WI see their last 32°F night by April 29; only one in ten is past it by April 11, and one in ten still has one after May 13. Planting tender crops after May 4 leaves a 30% risk of a frost on them, after May 8 20%, and after May 13 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 11 in half of years, as early as September 26 one year in ten, and holds off past October 26 one year in ten. A hard freeze of 28°F follows 12 days later, around October 23; in spring the one-in-ten date for 28°F is May 2, 11 days before the 32°F one. The freeze-free season lasts 165 days in a typical year, longer than at 74% of the 182 Wisconsin stations; it reaches 187 days one year in ten and falls short of 145 one year in ten. On average 141 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 9 days longer, to about May 8, and return around October 2. Severe cold of 16°F or below comes every winter, usually between November 19 and March 23.

July is the warmest month at Trempealeau Dam 6, WI, averaging 82°F by day and 63°F at night; January is the coldest at 25°F and 9°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 43% of years.

Warmth for growing adds up to 2,751 growing degree days a year (base 50°F), more than at 89% of the 182 Wisconsin stations. 34% of them (930) have built up by the end of June, and July adds the most, 693. Precipitation totals 34.6 inches a year, most in July (4.6") and least in January (1.1"); May to September bring 61% of it.

The nearest other station, Dodge, WI, 9 miles northwest of Trempealeau, has a last frost 6 days later (May 5), a first frost 6 days earlier (October 5), a season 13 days shorter.

The first measurable snow (0.1 inch or more) in Trempealeau usually arrives around December 3, and the last of the season around March 20. Those are the middle dates across the winters of 1991–2020 at Trempealeau Dam 6, WI, 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 40 days after the last snow.

ZIP 54661 is 2 miles from Trempealeau Dam 6, WI, which stands at 660 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 54630 (Galesville). The 2023 USDA Plant Hardiness Zone Map lists ZIP 54661 in zone 5a, the band where the coldest night of the year averaged -20 to -15°F (-28.9 to -26.1°C) over 1991–2020; a zone describes winter lows, not frost dates.