Frost Dates for 55449 — Blaine, Minnesota

Half of springs at Andover 1N, MN see their last 32°F night by May 5; only one in ten is past it by April 23, and one in ten still has one after May 21. Planting tender crops after May 11 leaves a 30% risk of a frost on them, after May 16 20%, and after May 21 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 2 in half of years, as early as September 18 one year in ten, and holds off past October 16 one year in ten. A hard freeze of 28°F follows 11 days later, around October 13; in spring the one-in-ten date for 28°F is May 9, 12 days before the 32°F one. The freeze-free season lasts 148 days in a typical year, shorter than at 59% of the 142 Minnesota stations; it reaches 168 days one year in ten and falls short of 128 one year in ten. On average 172 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 24. Severe cold of 16°F or below comes every winter, usually between November 10 and April 1.

July is the warmest month at Andover 1N, MN, averaging 82°F by day and 60°F at night; January is the coldest at 22°F and 2°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 66% of years.

Warmth for growing adds up to 2,396 growing degree days a year (base 50°F), fewer than at 52% of the 142 Minnesota stations. 32% of them (778) have built up by the end of June, and July adds the most, 647. Precipitation totals 28.8 inches a year, most in July (4.5") and least in January (0.6"); May to September bring 63% of it.

The nearest other station, Vadnais Lake, MN, 10 miles southeast of Blaine, has a last frost 12 days earlier (April 23), a first frost 18 days later (October 20), a season 29 days longer.

The first measurable snow (0.1 inch or more) in Blaine usually arrives around November 27, and the last of the season around March 24. Those are the middle dates across the winters of 1991–2020 at Vadnais Lake, MN, 9.7 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 42 days after the last snow.

ZIP 55449 is 7 miles from Andover 1N, MN, which stands at 899 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 55303 (Anoka). The 2023 USDA Plant Hardiness Zone Map lists ZIP 55449 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.