Frost Dates for 55101 — Saint Paul, Minnesota

Half of springs at St Paul Downtown Airport, MN see their last 32°F night by April 24; only one in ten is past it by April 9, and one in ten still has one after May 10. Planting tender crops after April 30 leaves a 30% risk of a frost on them, after May 4 20%, and after May 10 10%. The 16 days between the even-odds date and the one-in-ten date is wider than at 77% of the 142 Minnesota stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 16 in half of years, as early as October 2 one year in ten, and holds off past October 29 one year in ten. A hard freeze of 28°F follows 11 days later, around October 27; in spring the one-in-ten date for 28°F is April 28, 12 days before the 32°F one. The freeze-free season lasts 174 days in a typical year, longer than at 94% of the 142 Minnesota stations; it reaches 193 days one year in ten and falls short of 154 one year in ten. On average 146 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 4, and return around October 5. Severe cold of 16°F or below comes every winter, usually between November 21 and March 19.

July is the warmest month at St Paul Downtown Airport, MN, averaging 83°F by day and 64°F at night; January is the coldest at 24°F and 9°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 29% of years.

Warmth for growing adds up to 2,831 growing degree days a year (base 50°F), more than at 93% of the 142 Minnesota stations. 34% of them (950) have built up by the end of June, and July adds the most, 722. Precipitation totals 29.3 inches a year, most in June (4.6") and least in January (0.5"); May to September bring 68% of it.

The nearest other station, St Paul, MN, 3 miles southeast of Saint Paul and 200 feet higher, has a last frost 2 days later (April 26), a first frost 4 days earlier (October 12), a season 8 days shorter.

The first measurable snow (0.1 inch or more) in Saint Paul usually arrives around November 5, and the last of the season around April 11. Those are the middle dates across the winters of 1991–2020 at St Paul, MN, 2.9 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 13 days after the last snow.

ZIP 55101 is 3 miles from St Paul Downtown Airport, MN, which stands at 700 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 8 other ZIP codes share the station; its figures are presented in full for 55118 (West St Paul). The 2023 USDA Plant Hardiness Zone Map lists ZIP 55101 in zone 5a, the band where the coldest night of the year averaged -20 to -15°F (-28.9 to -26.1°C) over 1991–2020; a zone describes winter lows, not frost dates.