Frost Dates for 56537 — Fergus Falls, Minnesota

Half of springs at Fergus Falls, MN see their last 32°F night by May 4; only one in ten is past it by April 20, and one in ten still has one after May 18. Planting tender crops after May 10 leaves a 30% risk of a frost on them, after May 13 20%, and after May 18 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 37% of the 142 Minnesota stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 5 in half of years, as early as September 22 one year in ten, and holds off past October 19 one year in ten. A hard freeze of 28°F follows 10 days later, around October 15; in spring the one-in-ten date for 28°F is May 8, 10 days before the 32°F one. The freeze-free season lasts 152 days in a typical year, longer than at 53% of the 142 Minnesota stations; it reaches 172 days one year in ten and falls short of 134 one year in ten. On average 174 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 14, and return around September 27. Severe cold of 16°F or below comes every winter, usually between November 10 and April 1.

July is the warmest month at Fergus Falls, MN, averaging 81°F by day and 61°F at night; January is the coldest at 18°F and 0°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 67% of years.

Warmth for growing adds up to 2,356 growing degree days a year (base 50°F), fewer than at 56% of the 142 Minnesota stations. 32% of them (764) have built up by the end of June, and July adds the most, 643. Precipitation totals 27.0 inches a year, most in June (4.4") and least in December (0.7"); May to September bring 65% of it.

The nearest other station, Rothsay, MN, 17 miles northwest of Fergus Falls, has a last frost 1 day later (May 5), a first frost 2 days earlier (October 3), a season 3 days shorter.

The first measurable snow (0.1 inch or more) in Fergus Falls usually arrives around November 12, and the last of the season around April 1. Those are the middle dates across the winters of 1991–2020 at Fergus Falls, MN, 2.4 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 33 days after the last snow.

ZIP 56537 is 2 miles from Fergus Falls, MN, which stands at 1,250 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 56537 in zone 4a, the band where the coldest night of the year averaged -30 to -25°F (-34.4 to -31.7°C) over 1991–2020; a zone describes winter lows, not frost dates.