Frost Dates for 55021 — Faribault, Minnesota

Half of springs at Faribault, MN see their last 32°F night by May 5; only one in ten is past it by April 22, and one in ten still has one after May 19. Planting tender crops after May 11 leaves a 30% risk of a frost on them, after May 15 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 21 one year in ten, and holds off past October 17 one year in ten. A hard freeze of 28°F follows 8 days later, around October 13; in spring the one-in-ten date for 28°F is May 10, 9 days before the 32°F one. The freeze-free season lasts 152 days in a typical year, longer than at 53% of the 142 Minnesota stations; it reaches 171 days one year in ten and falls short of 132 one year in ten. On average 168 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 15, and return around September 27. Severe cold of 16°F or below comes every winter, usually between November 11 and March 29.

July is the warmest month at Faribault, MN, averaging 82°F by day and 61°F at night; January is the coldest at 23°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 68% of years.

Warmth for growing adds up to 2,529 growing degree days a year (base 50°F), more than at 63% of the 142 Minnesota stations. 33% of them (838) have built up by the end of June, and July adds the most, 660. Precipitation totals 35.5 inches a year, most in June (5.6") and least in January (1.0"); May to September bring 65% of it.

The nearest other station, Owatonna, MN, 14 miles south of Faribault and 170 feet higher, has the same 50% last-frost date, a first frost 1 day later (October 6), a season 2 days longer.

The first measurable snow (0.1 inch or more) in Faribault usually arrives around November 24, and the last of the season around April 1. Those are the middle dates across the winters of 1991–2020 at Faribault, MN, 1.4 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 34 days after the last snow.

ZIP 55021 is 1 mile from Faribault, MN, which stands at 970 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 55021 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.