Frost Dates for 56172 — Slayton, Minnesota

Half of springs at Lake Wilson, MN see their last 32°F night by May 7; only one in ten is past it by April 25, and one in ten still has one after May 19. Planting tender crops after May 11 leaves a 30% risk of a frost on them, after May 14 20%, and after May 19 10%. The 12 days between the even-odds date and the one-in-ten date is narrower than at 85% of the 142 Minnesota stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 29 in half of years, as early as September 15 one year in ten, and holds off past October 13 one year in ten. A hard freeze of 28°F follows 9 days later, around October 8; in spring the one-in-ten date for 28°F is May 10, 9 days before the 32°F one. The freeze-free season lasts 145 days in a typical year, shorter than at 65% of the 142 Minnesota stations; it reaches 164 days one year in ten and falls short of 127 one year in ten. On average 171 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 8 days longer, to about May 15, and return around September 20. Severe cold of 16°F or below comes every winter, usually between November 7 and April 1.

July is the warmest month at Lake Wilson, MN, averaging 81°F by day and 60°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 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 74% of years.

Warmth for growing adds up to 2,361 growing degree days a year (base 50°F), fewer than at 55% of the 142 Minnesota stations. 33% of them (776) have built up by the end of June, and July adds the most, 634. Precipitation totals 30.1 inches a year, most in June (5.0") and least in January (0.6"); May to September bring 64% of it.

The nearest other station, Tracy, MN, 17 miles north of Slayton and 250 feet lower, has a last frost 5 days earlier (May 2), a first frost 6 days later (October 5), a season 11 days longer.

The first measurable snow (0.1 inch or more) in Slayton usually arrives around November 12, and the last of the season around April 6. Those are the middle dates across the winters of 1991–2020 at Lake Wilson, MN, 9.5 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 31 days after the last snow.

ZIP 56172 is 10 miles from Lake Wilson, MN, which stands at 1,653 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 56172 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.