Frost Dates for 54022 — River Falls, Wisconsin

Half of springs at River Falls, WI see their last 32°F night by May 11; only one in ten is past it by April 26, and one in ten still has one after May 26. Planting tender crops after May 17 leaves a 30% risk of a frost on them, after May 21 20%, and after May 26 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 30% of the 182 Wisconsin stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 1 in half of years, as early as September 19 one year in ten, and holds off past October 15 one year in ten. A hard freeze of 28°F follows 10 days later, around October 11; in spring the one-in-ten date for 28°F is May 16, 10 days before the 32°F one. The freeze-free season lasts 143 days in a typical year, shorter than at 80% of the 182 Wisconsin stations; it reaches 162 days one year in ten and falls short of 122 one year in ten. On average 170 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 23, and return around September 24. Severe cold of 16°F or below comes every winter, usually between November 11 and April 2.

July is the warmest month at River Falls, WI, averaging 82°F by day and 58°F at night; January is the coldest at 22°F and 4°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 81% of years.

Warmth for growing adds up to 2,305 growing degree days a year (base 50°F), fewer than at 64% of the 182 Wisconsin stations. 32% of them (733) have built up by the end of June, and July adds the most, 617. Precipitation totals 34.3 inches a year, most in June (5.0") and least in January (0.9"); May to September bring 64% of it.

The nearest other station, Ellsworth 1E, WI, 12 miles southeast of River Falls, has a last frost 2 days later (May 13), a first frost 2 days earlier (September 29), a season 4 days shorter.

The first measurable snow (0.1 inch or more) in River Falls usually arrives around November 13, and the last of the season around April 5. Those are the middle dates across the winters of 1991–2020 at River Falls, WI, 0.2 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 36 days after the last snow.

ZIP 54022 is under a mile from River Falls, WI, which stands at 940 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 54022 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.