Frost Dates for 59255 — Poplar, Montana

Half of springs at Wolf Point 29 ENE, MT see their last 32°F night by May 24; only one in ten is past it by May 12, and one in ten still has one after June 6. Planting tender crops after May 29 leaves a 30% risk of a frost on them, after June 1 20%, and after June 6 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 74% of the 68 Montana stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 14 in half of years, as early as September 1 one year in ten, and holds off past September 25 one year in ten. A hard freeze of 28°F follows 8 days later, around September 22; in spring the one-in-ten date for 28°F is May 26, 11 days before the 32°F one. The freeze-free season lasts 110 days in a typical year, shorter than at 79% of the 68 Montana stations; it reaches 127 days one year in ten and falls short of 92 one year in ten. On average 206 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 June 3, and return around September 4. Severe cold of 16°F or below comes every winter, usually between October 19 and April 12.

July is the warmest month at Wolf Point 29 ENE, MT, averaging 84°F by day and 53°F at night; January is the coldest at 23°F and 0°F. A freezing night is all but certain in every month from September to May (a 90% chance or more). From July to August the chance of a 32°F night stays under 10% each month. In spring, June still brings one in 21% of years.

Warmth for growing adds up to 1,888 growing degree days a year (base 50°F), more than at 54% of the 68 Montana stations. 28% of them (521) have built up by the end of June, and July adds the most, 566. Precipitation totals 14.2 inches a year, most in June (2.9") and least in February (0.3"); May to September bring 72% of it.

The nearest other station, Wolf Pt, MT, 23 miles west of Poplar, has a last frost 16 days earlier (May 8), a first frost 14 days later (September 28), a season 33 days longer.

The first measurable snow (0.1 inch or more) in Poplar usually arrives around December 4, and the last of the season around February 26. Those are the middle dates across the winters of 1991–2020 at Vida 6 NE, MT, 20.1 miles away: half of years saw snow earlier, half later. Snow fell in 88% of those winters. The last 32°F night of spring typically comes 87 days after the last snow.

ZIP 59255 is 12 miles from Wolf Point 29 ENE, MT, which stands at 2,085 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 59255 in zone 4a, the band where the coldest night of the year averaged -30 to -25°F (-34.4 to -31.7°C) over 1991–2020; a zone describes winter lows, not frost dates.