Frost Dates for 54629 — Fountain City, Wisconsin

Half of springs at Winona Dam 5 A, MN see their last 32°F night by April 23; only one in ten is past it by April 7, and one in ten still has one after May 6. Planting tender crops after April 29 leaves a 30% risk of a frost on them, after May 2 20%, and after May 6 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 84% of the 182 Wisconsin stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 21 in half of years, as early as October 7 one year in ten, and holds off past November 4 one year in ten. A hard freeze of 28°F follows 11 days later, around November 1; in spring the one-in-ten date for 28°F is April 27, 9 days before the 32°F one. The freeze-free season lasts 180 days in a typical year, longer than at 96% of the 182 Wisconsin stations; it reaches 201 days one year in ten and falls short of 161 one year in ten. On average 148 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 10 days longer, to about May 3, and return around October 10. Severe cold of 16°F or below comes every winter, usually between November 25 and March 19.

July is the warmest month at Winona Dam 5 A, MN, averaging 83°F by day and 63°F at night; January is the coldest at 25°F and 8°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 24% of years.

Warmth for growing adds up to 2,817 growing degree days a year (base 50°F), more than at 92% of the 182 Wisconsin stations. 33% of them (917) have built up by the end of June, and July adds the most, 705. Precipitation totals 34.5 inches a year, most in June (4.8") and least in February (1.0"); May to September bring 61% of it.

The nearest other station, Dodge, WI, 6 miles east of Fountain City, has a last frost 12 days later (May 5), a first frost 16 days earlier (October 5), a season 28 days shorter.

The first measurable snow (0.1 inch or more) in Fountain City usually arrives around November 29, and the last of the season around March 19. Those are the middle dates across the winters of 1991–2020 at Winona Dam 5 A, MN, 3.2 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 35 days after the last snow.

ZIP 54629 is 3 miles from Winona Dam 5 A, MN, which stands at 663 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 54629 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.