Frost Dates for 58318 — Bottineau, North Dakota

Half of springs at Bottineau, ND see their last 32°F night by May 15; only one in ten is past it by May 2, and one in ten still has one after May 28. Planting tender crops after May 21 leaves a 30% risk of a frost on them, after May 24 20%, and after May 28 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 21% of the 33 North Dakota stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 25 in half of years, as early as September 13 one year in ten, and holds off past October 7 one year in ten. A hard freeze of 28°F follows 7 days later, around October 2; in spring the one-in-ten date for 28°F is May 20, 8 days before the 32°F one. The freeze-free season lasts 133 days in a typical year, shorter than at 73% of the 33 North Dakota stations; it reaches 150 days one year in ten and falls short of 114 one year in ten. On average 196 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 25, and return around September 18. Severe cold of 16°F or below comes every winter, usually between October 28 and April 7.

July is the warmest month at Bottineau, ND, averaging 79°F by day and 56°F at night; January is the coldest at 15°F and -4°F. A freezing night is all but certain in every month from October to May (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month.

Warmth for growing adds up to 1,911 growing degree days a year (base 50°F), fewer than at 85% of the 33 North Dakota stations. 30% of them (579) have built up by the end of June, and July adds the most, 549. Precipitation totals 19.3 inches a year, most in June (3.9") and least in January (0.5"); May to September bring 69% of it.

The nearest other station, Belcourt Keya Radio, ND, 30 miles east of Bottineau and 341 feet higher, has a last frost 4 days later (May 19), a first frost 1 day earlier (September 24), a season 7 days shorter.

The first measurable snow (0.1 inch or more) in Bottineau usually arrives around October 25, and the last of the season around April 17. Those are the middle dates across the winters of 1991–2020 at Bottineau, ND, 3.5 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 28 days after the last snow.

ZIP 58318 is 4 miles from Bottineau, ND, which stands at 1,619 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 58318 in zone 3b, the band where the coldest night of the year averaged -35 to -30°F (-37.2 to -34.4°C) over 1991–2020; a zone describes winter lows, not frost dates.