Frost Dates for 55375 — St Bonifacius, Minnesota

Half of springs at Chaska 2NW, MN see their last 32°F night by May 5; only one in ten is past it by April 21, and one in ten still has one after May 19. Planting tender crops after May 10 leaves a 30% risk of a frost on them, after May 14 20%, and after May 19 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 37% of the 142 Minnesota stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 5 in half of years, as early as September 22 one year in ten, and holds off past October 18 one year in ten. A hard freeze of 28°F follows 11 days later, around October 16; in spring the one-in-ten date for 28°F is May 6, 13 days before the 32°F one. The freeze-free season lasts 151 days in a typical year, shorter than at 48% of the 142 Minnesota stations; it reaches 169 days one year in ten and falls short of 133 one year in ten. On average 161 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 11 days longer, to about May 16, and return around September 27. Severe cold of 16°F or below comes every winter, usually between November 13 and March 31.

July is the warmest month at Chaska 2NW, MN, averaging 83°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 69% of years.

Warmth for growing adds up to 2,486 growing degree days a year (base 50°F), more than at 56% of the 142 Minnesota stations. 32% of them (789) have built up by the end of June, and July adds the most, 663. Precipitation totals 34.2 inches a year, most in June (5.3") and least in January (0.9"); May to September bring 63% of it.

The nearest other station, Chanhassen Wsfo, MN, 10 miles southeast of St Bonifacius, has a last frost 5 days earlier (April 30), a first frost 4 days later (October 9), a season 9 days longer.

The first measurable snow (0.1 inch or more) in St Bonifacius usually arrives around November 8, and the last of the season around April 10. Those are the middle dates across the winters of 1991–2020 at Chanhassen Wsfo, MN, 9.6 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 25 days after the last snow.

ZIP 55375 is 9 miles from Chaska 2NW, MN, which stands at 923 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 6 other ZIP codes share the station; its figures are presented in full for 55318 (Chaska). The 2023 USDA Plant Hardiness Zone Map lists ZIP 55375 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.