Frost Dates for 55051 — Mora, Minnesota

Half of springs at Mora, MN see their last 32°F night by May 9; only one in ten is past it by April 26, and one in ten still has one after May 26. Planting tender crops after May 16 leaves a 30% risk of a frost on them, after May 20 20%, and after May 26 10%. The 17 days between the even-odds date and the one-in-ten date is wider than at 89% 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 12 one year in ten. A hard freeze of 28°F follows 9 days later, around October 9; in spring the one-in-ten date for 28°F is May 14, 12 days before the 32°F one. The freeze-free season lasts 142 days in a typical year, shorter than at 73% of the 142 Minnesota stations; it reaches 161 days one year in ten and falls short of 123 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 21, and return around September 21. Severe cold of 16°F or below comes every winter, usually between November 10 and March 31.

July is the warmest month at Mora, MN, averaging 80°F by day and 58°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 76% of years.

Warmth for growing adds up to 2,148 growing degree days a year (base 50°F), fewer than at 69% of the 142 Minnesota stations. 32% of them (683) have built up by the end of June, and July adds the most, 594. Precipitation totals 31.9 inches a year, most in July (4.7") and least in January (0.7"); May to September bring 64% of it.

The nearest other station, Hinckley, MN, 16 miles northeast of Mora, has a last frost 7 days later (May 16), a first frost 6 days earlier (September 24), a season 12 days shorter.

The first measurable snow (0.1 inch or more) in Mora usually arrives around November 13, and the last of the season around April 12. Those are the middle dates across the winters of 1991–2020 at Mora, MN, 1.7 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 55051 is 2 miles from Mora, MN, which stands at 1,018 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 55051 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.