Frost Dates for 54814 — Bayfield, Wisconsin

Half of springs at Bayfield 6 N, WI see their last 32°F night by May 20; only one in ten is past it by May 2, and one in ten still has one after June 5. Planting tender crops after May 27 leaves a 30% risk of a frost on them, after May 31 20%, and after June 5 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 8 in half of years, as early as September 21 one year in ten, and holds off past October 26 one year in ten. A hard freeze of 28°F follows 16 days later, around October 24; in spring the one-in-ten date for 28°F is May 20, 16 days before the 32°F one. The freeze-free season lasts 141 days in a typical year, shorter than at 82% of the 182 Wisconsin stations; it reaches 164 days one year in ten and falls short of 117 one year in ten. On average 177 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 14 days longer, to about June 3, and return around September 26. Severe cold of 16°F or below comes every winter, usually between November 18 and April 4.

July is the warmest month at Bayfield 6 N, WI, averaging 77°F by day and 56°F at night; January is the coldest at 22°F and 7°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 89% of years and June still brings one in 20% of years.

Warmth for growing adds up to 1,794 growing degree days a year (base 50°F), fewer than at 95% of the 182 Wisconsin stations. 26% of them (472) have built up by the end of June, and July adds the most, 511. Precipitation totals 33.2 inches a year, most in July (4.1") and least in February (1.1"); May to September bring 55% of it.

The nearest other station, Bayfield Fish Hatchery, WI, 5 miles south of Bayfield and 205 feet lower, has a last frost 3 days later (May 23), a first frost 6 days earlier (October 2), a season 10 days shorter.

The first measurable snow (0.1 inch or more) in Bayfield usually arrives around November 2, and the last of the season around April 24. Those are the middle dates across the winters of 1991–2020 at Bayfield 6 N, WI, 2.5 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 54814 is 3 miles from Bayfield 6 N, WI, which stands at 820 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 54814 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.