Frost Dates for 54806 — Ashland, Wisconsin

Half of springs at Ashland 3S, WI see their last 32°F night by May 20; only one in ten is past it by May 3, and one in ten still has one after June 3. Planting tender crops after May 26 leaves a 30% risk of a frost on them, after May 30 20%, and after June 3 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 58% 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 19 one year in ten, and holds off past October 15 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 21, 13 days before the 32°F one. The freeze-free season lasts 133 days in a typical year, shorter than at 92% of the 182 Wisconsin stations; it reaches 155 days one year in ten and falls short of 113 one year in ten. On average 180 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 13 days longer, to about June 2, and return around September 22. Severe cold of 16°F or below comes every winter, usually between November 14 and April 3.

July is the warmest month at Ashland 3S, WI, averaging 78°F by day and 56°F at night; January is the coldest at 21°F and 4°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 17% of years.

Warmth for growing adds up to 1,844 growing degree days a year (base 50°F), fewer than at 93% of the 182 Wisconsin stations. 27% of them (499) have built up by the end of June, and July adds the most, 533.

The nearest other station, Bayfield Fish Hatchery, WI, 15 miles north of Ashland and 211 feet lower, has a last frost 3 days later (May 23), the same first-frost date, a season 2 days shorter.

The first measurable snow (0.1 inch or more) in Ashland usually arrives around November 16, and the last of the season around April 16. Those are the middle dates across the winters of 1991–2020 at Ashland 3S, WI, 1.9 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 34 days after the last snow.

ZIP 54806 is 2 miles from Ashland 3S, WI, which stands at 826 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 54806 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.