Frost Dates for 55975 — Spring Valley, Minnesota

Half of springs at Grand Meadow, MN see their last 32°F night by May 6; only one in ten is past it by April 23, and one in ten still has one after May 18. Planting tender crops after May 11 leaves a 30% risk of a frost on them, after May 14 20%, and after May 18 10%. The 12 days between the even-odds date and the one-in-ten date is narrower than at 85% of the 142 Minnesota stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 1 in half of years, as early as September 17 one year in ten, and holds off past October 13 one year in ten. A hard freeze of 28°F follows 8 days later, around October 9; in spring the one-in-ten date for 28°F is May 10, 8 days before the 32°F one. The freeze-free season lasts 146 days in a typical year, shorter than at 64% of the 142 Minnesota stations; it reaches 165 days one year in ten and falls short of 128 one year in ten. On average 171 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 8 days longer, to about May 14, and return around September 22. Severe cold of 16°F or below comes every winter, usually between November 10 and March 31.

July is the warmest month at Grand Meadow, MN, averaging 79°F by day and 59°F at night; January is the coldest at 21°F and 5°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 72% of years.

Warmth for growing adds up to 2,226 growing degree days a year (base 50°F), fewer than at 64% of the 142 Minnesota stations. 33% of them (735) have built up by the end of June, and July adds the most, 587. Precipitation totals 37.6 inches a year, most in June (5.7") and least in February (0.9"); May to September bring 63% of it.

The nearest other station, Preston, MN, 15 miles east of Spring Valley and 420 feet lower, has a last frost 8 days later (May 14), a first frost 3 days earlier (September 28), a season 10 days shorter.

The first measurable snow (0.1 inch or more) in Spring Valley usually arrives around November 16, and the last of the season around April 12. Those are the middle dates across the winters of 1991–2020 at Spring Valley, MN, 1.1 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 24 days after the last snow.

ZIP 55975 is 10 miles from Grand Meadow, MN, which stands at 1,350 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 55975 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.