Frost Dates for 58854 — Watford City, North Dakota

Half of springs at Watford City, ND see their last 32°F night by May 9; only one in ten is past it by April 28, and one in ten still has one after May 22. Planting tender crops after May 14 leaves a 30% risk of a frost on them, after May 17 20%, and after May 22 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 27 in half of years, as early as September 15 one year in ten, and holds off past October 11 one year in ten. A hard freeze of 28°F follows 10 days later, around October 7; in spring the one-in-ten date for 28°F is May 13, 9 days before the 32°F one. The freeze-free season lasts 139 days in a typical year, longer than at 58% of the 33 North Dakota stations; it reaches 159 days one year in ten and falls short of 122 one year in ten. On average 194 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 19, and return around September 20. Severe cold of 16°F or below comes every winter, usually between November 4 and April 2.

July is the warmest month at Watford City, ND, averaging 82°F by day and 58°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 84% of years.

Warmth for growing adds up to 2,147 growing degree days a year (base 50°F), fewer than at 58% of the 33 North Dakota stations. 29% of them (620) have built up by the end of June, and July adds the most, 622. Precipitation totals 15.7 inches a year, most in June (3.4") and least in February (0.4"); May to September bring 70% of it.

The nearest other station, Keene 3S, ND, 15 miles east of Watford City and 300 feet higher, has a last frost 11 days later (May 20), a first frost 7 days earlier (September 20), a season 18 days shorter.

The first measurable snow (0.1 inch or more) in Watford City usually arrives around October 31, and the last of the season around April 20. Those are the middle dates across the winters of 1991–2020 at Watford City, ND, 3.7 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 19 days after the last snow.

ZIP 58854 is 4 miles from Watford City, ND, which stands at 2,170 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 58854 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.