Frost Dates for 55327 — Dayton, Minnesota

Half of springs at Elk Rvr, MN see their last 32°F night by May 4; only one in ten is past it by April 22, and one in ten still has one after May 18. Planting tender crops after May 10 leaves a 30% risk of a frost on them, after May 13 20%, and after May 18 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 23 one year in ten, and holds off past October 18 one year in ten. A hard freeze of 28°F follows 12 days later, around October 17; in spring the one-in-ten date for 28°F is May 9, 9 days before the 32°F one. The freeze-free season lasts 154 days in a typical year, longer than at 61% of the 142 Minnesota stations; it reaches 171 days one year in ten and falls short of 135 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 13, and return around September 28. Severe cold of 16°F or below comes every winter, usually between November 14 and March 31.

July is the warmest month at Elk Rvr, MN, averaging 83°F by day and 61°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 65% of years.

Warmth for growing adds up to 2,508 growing degree days a year (base 50°F), more than at 59% of the 142 Minnesota stations. 33% of them (823) have built up by the end of June, and July adds the most, 686. Precipitation totals 32.9 inches a year, most in June (4.5") and least in January (0.8"); May to September bring 63% of it.

The nearest other station, Andover 1N, MN, 9 miles east of Dayton, has a last frost 1 day later (May 5), a first frost 3 days earlier (October 2), a season 6 days shorter.

The first measurable snow (0.1 inch or more) in Dayton usually arrives around November 12, and the last of the season around April 7. Those are the middle dates across the winters of 1991–2020 at Elk Rvr, MN, 8 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 55327 is 8 miles from Elk Rvr, MN, which stands at 880 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 5 other ZIP codes share the station; its figures are presented in full for 55330 (Elk River). The 2023 USDA Plant Hardiness Zone Map lists ZIP 55327 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.