Frost Dates for 55923 — Chatfield, Minnesota

Half of springs at Preston, MN see their last 32°F night by May 14; only one in ten is past it by May 1, and one in ten still has one after May 27. Planting tender crops after May 20 leaves a 30% risk of a frost on them, after May 23 20%, and after May 27 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 28 in half of years, as early as September 15 one year in ten, and holds off past October 9 one year in ten. A hard freeze of 28°F follows 7 days later, around October 5; in spring the one-in-ten date for 28°F is May 18, 9 days before the 32°F one. The freeze-free season lasts 136 days in a typical year, shorter than at 85% of the 142 Minnesota stations; it reaches 153 days one year in ten and falls short of 118 one year in ten. On average 166 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 24, and return around September 19. Severe cold of 16°F or below comes every winter, usually between November 5 and April 2.

July is the warmest month at Preston, MN, averaging 81°F by day and 58°F at night; January is the coldest at 24°F and 4°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 2,307 growing degree days a year (base 50°F), fewer than at 61% of the 142 Minnesota stations. 33% of them (755) have built up by the end of June, and July adds the most, 609. Precipitation totals 36.8 inches a year, most in June (6.0") and least in January (1.1"); May to September bring 62% of it.

The nearest other station, Rochester International Airport, MN, 17 miles west of Chatfield and 374 feet higher, has a last frost 14 days earlier (April 30), a first frost 8 days later (October 6), a season 23 days longer.

The first measurable snow (0.1 inch or more) in Chatfield usually arrives around November 13, and the last of the season around April 11. Those are the middle dates across the winters of 1991–2020 at Preston, MN, 12.4 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 55923 is 12 miles from Preston, MN, which stands at 930 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 55923 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.