Frost Dates for 56215 — Benson, Minnesota

Half of springs at Benson, MN see their last 32°F night by May 4; only one in ten is past it by April 22, and one in ten still has one after May 17. Planting tender crops after May 10 leaves a 30% risk of a frost on them, after May 13 20%, and after May 17 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 61% of the 142 Minnesota stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 3 in half of years, as early as September 21 one year in ten, and holds off past October 15 one year in ten. A hard freeze of 28°F follows 9 days later, around October 12; in spring the one-in-ten date for 28°F is May 8, 9 days before the 32°F one. The freeze-free season lasts 151 days in a typical year, shorter than at 48% of the 142 Minnesota stations; it reaches 170 days one year in ten and falls short of 132 one year in ten. On average 168 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 9 days longer, to about May 13, and return around September 26. Severe cold of 16°F or below comes every winter, usually between November 8 and April 1.

July is the warmest month at Benson, MN, averaging 83°F by day and 61°F at night; January is the coldest at 21°F and 1°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 68% of years.

Warmth for growing adds up to 2,620 growing degree days a year (base 50°F), more than at 71% of the 142 Minnesota stations. 33% of them (874) have built up by the end of June, and July adds the most, 686. Precipitation totals 28.1 inches a year, most in June (4.1") and least in January (0.7"); May to September bring 64% of it.

The nearest other station, Milan 1NW, MN, 22 miles southwest of Benson, has a last frost 1 day earlier (May 3), a first frost 1 day earlier (October 2).

The first measurable snow (0.1 inch or more) in Benson usually arrives around November 11, and the last of the season around April 8. Those are the middle dates across the winters of 1991–2020 at Benson, MN, 2.2 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 56215 is 2 miles from Benson, MN, which stands at 1,030 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 56215 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.