Frost Dates for 55956 — Mazeppa, Minnesota

Half of springs at Zumbrota, MN see their last 32°F night by May 9; only one in ten is past it by April 24, and one in ten still has one after May 22. Planting tender crops after May 14 leaves a 30% risk of a frost on them, after May 17 20%, and after May 22 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 September 30 in half of years, as early as September 17 one year in ten, and holds off past October 11 one year in ten. A hard freeze of 28°F follows 8 days later, around October 8; in spring the one-in-ten date for 28°F is May 12, 10 days before the 32°F one. The freeze-free season lasts 144 days in a typical year, shorter than at 67% of the 142 Minnesota stations; it reaches 163 days one year in ten and falls short of 127 one year in ten. On average 163 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 18, and return around September 21. Severe cold of 16°F or below comes every winter, usually between November 7 and March 30.

July is the warmest month at Zumbrota, MN, averaging 81°F by day and 60°F at night; January is the coldest at 23°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 75% of years.

Warmth for growing adds up to 2,419 growing degree days a year (base 50°F), more than at 50% of the 142 Minnesota stations. 33% of them (803) have built up by the end of June, and July adds the most, 637. Precipitation totals 35.2 inches a year, most in June (5.3") and least in January (1.0"); May to September bring 64% of it.

The nearest other station, Byron 4north, MN, 14 miles southwest of Mazeppa, has a last frost 3 days later (May 12), a first frost 2 days earlier (September 28), a season 5 days shorter.

The first measurable snow (0.1 inch or more) in Mazeppa usually arrives around November 10, and the last of the season around April 11. Those are the middle dates across the winters of 1991–2020 at Zumbrota, MN, 6.7 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 28 days after the last snow.

ZIP 55956 is 7 miles from Zumbrota, MN, which stands at 970 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 4 other ZIP codes share the station; its figures are presented in full for 55992 (Zumbrota). The 2023 USDA Plant Hardiness Zone Map lists ZIP 55956 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.