Frost Dates for 54015 — Hammond, Wisconsin

Half of springs at Baldwin, WI see their last 32°F night by May 6; only one in ten is past it by April 21, and one in ten still has one after May 21. Planting tender crops after May 12 leaves a 30% risk of a frost on them, after May 16 20%, and after May 21 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 2 in half of years, as early as September 18 one year in ten, and holds off past October 17 one year in ten. A hard freeze of 28°F follows 10 days later, around October 12; in spring the one-in-ten date for 28°F is May 12, 9 days before the 32°F one. The freeze-free season lasts 148 days in a typical year, shorter than at 69% of the 182 Wisconsin stations; it reaches 168 days one year in ten and falls short of 128 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 10 days longer, to about May 16, and return around September 24. Severe cold of 16°F or below comes every winter, usually between November 11 and March 31.

July is the warmest month at Baldwin, WI, averaging 79°F by day and 59°F at night; January is the coldest at 20°F and 2°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 69% of years.

Warmth for growing adds up to 2,241 growing degree days a year (base 50°F), fewer than at 71% of the 182 Wisconsin stations. 33% of them (737) have built up by the end of June, and July adds the most, 593. Precipitation totals 33.0 inches a year, most in June (5.2") and least in January (0.8"); May to September bring 65% of it.

The nearest other station, River Falls, WI, 11 miles southwest of Hammond and 160 feet lower, has a last frost 5 days later (May 11), a first frost 1 day earlier (October 1), a season 5 days shorter.

The first measurable snow (0.1 inch or more) in Hammond usually arrives around November 16, and the last of the season around April 5. Those are the middle dates across the winters of 1991–2020 at Baldwin, WI, 2.7 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 31 days after the last snow.

ZIP 54015 is 3 miles from Baldwin, WI, which stands at 1,100 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 6 other ZIP codes share the station; its figures are presented in full for 54017 (New Richmond). The 2023 USDA Plant Hardiness Zone Map lists ZIP 54015 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.