Frost Dates for 55049 — Medford, Minnesota

Half of springs at Owatonna, MN see their last 32°F night by May 5; only one in ten is past it by April 20, and one in ten still has one after May 20. Planting tender crops after May 10 leaves a 30% risk of a frost on them, after May 14 20%, and after May 20 10%. The 15 days between the even-odds date and the one-in-ten date is wider than at 64% of the 142 Minnesota stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 6 in half of years, as early as September 23 one year in ten, and holds off past October 21 one year in ten. A hard freeze of 28°F follows 12 days later, around October 18; in spring the one-in-ten date for 28°F is May 12, 8 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 173 days one year in ten and falls short of 136 one year in ten. On average 160 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 14, and return around September 29. Severe cold of 16°F or below comes every winter, usually between November 14 and March 28.

July is the warmest month at Owatonna, MN, averaging 82°F by day and 62°F at night; January is the coldest at 22°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 67% of years.

Warmth for growing adds up to 2,644 growing degree days a year (base 50°F), more than at 76% of the 142 Minnesota stations. 33% of them (874) have built up by the end of June, and July adds the most, 677. Precipitation totals 35.6 inches a year, most in June (5.3") and least in January (0.9"); May to September bring 65% of it.

The nearest other station, Faribault, MN, 10 miles north of Medford and 170 feet lower, has the same 50% last-frost date, a first frost 1 day earlier (October 5), a season 2 days shorter.

The first measurable snow (0.1 inch or more) in Medford usually arrives around November 13, and the last of the season around March 25. Those are the middle dates across the winters of 1991–2020 at Owatonna, MN, 5.2 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 41 days after the last snow.

ZIP 55049 is 5 miles from Owatonna, MN, which stands at 1,140 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 55060 (Owatonna). The 2023 USDA Plant Hardiness Zone Map lists ZIP 55049 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.