Frost Dates for 53104 — Bristol, Wisconsin

Half of springs at Paddock Lake, WI see their last 32°F night by April 30; only one in ten is past it by April 15, and one in ten still has one after May 16. Planting tender crops after May 6 leaves a 30% risk of a frost on them, after May 10 20%, and after May 16 10%. The 16 days between the even-odds date and the one-in-ten date is wider than at 70% of the 182 Wisconsin stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 15 in half of years, as early as September 30 one year in ten, and holds off past October 27 one year in ten. A hard freeze of 28°F follows 11 days later, around October 26; in spring the one-in-ten date for 28°F is May 3, 13 days before the 32°F one. The freeze-free season lasts 167 days in a typical year, longer than at 79% of the 182 Wisconsin stations; it reaches 186 days one year in ten and falls short of 147 one year in ten. On average 146 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 12, and return around October 4. Severe cold of 16°F or below comes every winter, usually between November 26 and March 17.

July is the warmest month at Paddock Lake, WI, averaging 83°F by day and 61°F at night; January is the coldest at 29°F and 13°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 48% of years.

Warmth for growing adds up to 2,634 growing degree days a year (base 50°F), more than at 75% of the 182 Wisconsin stations. 32% of them (838) have built up by the end of June, and July adds the most, 669. Precipitation totals 37.7 inches a year, most in May (4.4") and least in January (1.7"); May to September bring 51% of it.

The nearest other station, Antioch, IL, 6 miles southwest of Bristol, has a last frost 7 days earlier (April 23), a first frost 6 days later (October 21), a season 12 days longer.

The first measurable snow (0.1 inch or more) in Bristol usually arrives around November 16, and the last of the season around April 4. Those are the middle dates across the winters of 1991–2020 at Lake Villa 2NE, IL, 8.4 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 26 days after the last snow.

ZIP 53104 is 3 miles from Paddock Lake, WI, which stands at 775 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 53168 (Salem). The 2023 USDA Plant Hardiness Zone Map lists ZIP 53104 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.