Frost Dates for 54971 — Ripon, Wisconsin

Half of springs at Ripon 5 NE, WI see their last 32°F night by May 1; only one in ten is past it by April 16, and one in ten still has one after May 14. Planting tender crops after May 6 leaves a 30% risk of a frost on them, after May 9 20%, and after May 14 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 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 13 days later, around October 24; in spring the one-in-ten date for 28°F is May 5, 9 days before the 32°F one. The freeze-free season lasts 163 days in a typical year, longer than at 69% of the 182 Wisconsin stations; it reaches 182 days one year in ten and falls short of 142 one year in ten. On average 153 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 11, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 23 and March 21.

July is the warmest month at Ripon 5 NE, WI, averaging 80°F by day and 60°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 50% of years.

Warmth for growing adds up to 2,409 growing degree days a year (base 50°F), fewer than at 52% of the 182 Wisconsin stations. 32% of them (783) have built up by the end of June, and July adds the most, 620. Precipitation totals 31.5 inches a year, most in June (4.8") and least in February (0.9"); May to September bring 60% of it.

The nearest other station, Berlin Wwtp, WI, 11 miles northwest of Ripon and 164 feet lower, has the same 50% last-frost date, a first frost 3 days earlier (October 8), a season 5 days shorter.

The first measurable snow (0.1 inch or more) in Ripon usually arrives around November 22, and the last of the season around April 2. Those are the middle dates across the winters of 1991–2020 at Ripon 5 NE, WI, 5.6 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 29 days after the last snow.

ZIP 54971 is 6 miles from Ripon 5 NE, WI, which stands at 930 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 54971 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.