Frost Dates for 69337 — Chadron, Nebraska

Half of springs at Chadron 3SW, NE 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 31. Planting tender crops after May 21 leaves a 30% risk of a frost on them, after May 25 20%, and after May 31 10%. The 16 days between the even-odds date and the one-in-ten date is wider than at 94% of the 68 Nebraska stations behind this site's ZIP pages.

In fall the first 32°F night comes by September 28 in half of years, as early as September 13 one year in ten, and holds off past October 11 one year in ten. A hard freeze of 28°F follows 9 days later, around October 7; in spring the one-in-ten date for 28°F is May 19, 12 days before the 32°F one. The freeze-free season lasts 133 days in a typical year, shorter than at 99% of the 68 Nebraska stations; it reaches 151 days one year in ten and falls short of 113 one year in ten. On average 173 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 26, and return around September 18. Severe cold of 16°F or below comes every winter, usually between November 2 and April 2.

July is the warmest month at Chadron 3SW, NE, averaging 89°F by day and 59°F at night; January is the coldest at 38°F and 13°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 2,744 growing degree days a year (base 50°F), fewer than at 93% of the 68 Nebraska stations. 29% of them (802) have built up by the end of June, and July adds the most, 742. Precipitation totals 18.7 inches a year, most in June (3.2") and least in January (0.6"); May to September bring 60% of it.

The nearest other station, Oglala 1S, SD, 28 miles northeast of Chadron and 388 feet lower, has a last frost 8 days earlier (May 7), a first frost 6 days later (October 4), a season 16 days longer.

The first measurable snow (0.1 inch or more) in Chadron usually arrives around October 30, and the last of the season around April 19. Those are the middle dates across the winters of 1991–2020 at Chadron 3SW, NE, 2.6 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 26 days after the last snow.

ZIP 69337 is 3 miles from Chadron 3SW, NE, which stands at 3,383 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 69337 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.