Frost Dates for 56360 — Osakis, Minnesota

Half of springs at Long Prairie, MN see their last 32°F night by May 13; only one in ten is past it by May 1, and one in ten still has one after May 28. Planting tender crops after May 19 leaves a 30% risk of a frost on them, after May 23 20%, and after May 28 10%. The 15 days between the even-odds date and the one-in-ten date is wider than at 64% of the 142 Minnesota stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 27 in half of years, as early as September 13 one year in ten, and holds off past October 10 one year in ten. A hard freeze of 28°F follows 8 days later, around October 5; in spring the one-in-ten date for 28°F is May 17, 11 days before the 32°F one. The freeze-free season lasts 134 days in a typical year, shorter than at 89% of the 142 Minnesota stations; it reaches 152 days one year in ten and falls short of 114 one year in ten. On average 179 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 12 days longer, to about May 25, and return around September 17. Severe cold of 16°F or below comes every winter, usually between November 4 and April 7.

July is the warmest month at Long Prairie, MN, averaging 79°F by day and 57°F at night; January is the coldest at 18°F and -1°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month.

Warmth for growing adds up to 1,952 growing degree days a year (base 50°F), fewer than at 83% of the 142 Minnesota stations. 31% of them (607) have built up by the end of June, and July adds the most, 552. Precipitation totals 31.0 inches a year, most in June (4.6") and least in February (0.9"); May to September bring 63% of it.

The nearest other station, Alexandria Municipal Airport, MN, 14 miles west of Osakis, has a last frost 11 days earlier (May 2), a first frost 11 days later (October 8), a season 25 days longer.

The first measurable snow (0.1 inch or more) in Osakis usually arrives around October 30, and the last of the season around April 16. Those are the middle dates across the winters of 1991–2020 at Long Prairie, MN, 11.7 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 27 days after the last snow.

ZIP 56360 is 12 miles from Long Prairie, MN, which stands at 1,340 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 56347 (Long Prairie). The 2023 USDA Plant Hardiness Zone Map lists ZIP 56360 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.