Frost Dates for 53575 — Oregon, Wisconsin

Half of springs at Uw Arboretum - Madison, WI see their last 32°F night by May 1; only one in ten is past it by April 18, and one in ten still has one after May 17. Planting tender crops after May 7 leaves a 30% risk of a frost on them, after May 11 20%, and after May 17 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 9 in half of years, as early as September 26 one year in ten, and holds off past October 24 one year in ten. A hard freeze of 28°F follows 11 days later, around October 20; in spring the one-in-ten date for 28°F is May 3, 14 days before the 32°F one. The freeze-free season lasts 161 days in a typical year, longer than at 62% of the 182 Wisconsin stations; it reaches 179 days one year in ten and falls short of 140 one year in ten. On average 157 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 13, and return around October 1. Severe cold of 16°F or below comes every winter, usually between November 21 and March 21.

July is the warmest month at Uw Arboretum - Madison, WI, averaging 82°F by day and 61°F at night; January is the coldest at 28°F and 11°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 51% of years.

Warmth for growing adds up to 2,708 growing degree days a year (base 50°F), more than at 84% of the 182 Wisconsin stations. 33% of them (899) have built up by the end of June, and July adds the most, 676. Precipitation totals 40.1 inches a year, most in June (5.7") and least in January (1.7"); May to September bring 57% of it.

The nearest other station, Stoughton, WI, 9 miles east of Oregon, has a last frost 1 day earlier (April 30), a first frost 2 days later (October 11), a season 2 days longer.

The first measurable snow (0.1 inch or more) in Oregon usually arrives around December 2, and the last of the season around March 23. Those are the middle dates across the winters of 1991–2020 at Uw Arboretum - Madison, WI, 8 miles away: half of years saw snow earlier, half later. Snow fell in 97% of those winters. The last 32°F night of spring typically comes 39 days after the last snow.

ZIP 53575 is 8 miles from Uw Arboretum - Madison, WI, which stands at 870 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 8 other ZIP codes share the station; its figures are presented in full for 53711 (Madison). The 2023 USDA Plant Hardiness Zone Map lists ZIP 53575 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.