Frost Dates for 68739 — Hartington, Nebraska

Half of springs at Hartington, NE see their last 32°F night by April 30; only one in ten is past it by April 17, and one in ten still has one after May 13. Planting tender crops after May 5 leaves a 30% risk of a frost on them, after May 9 20%, and after May 13 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 29% of the 68 Nebraska stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 5 in half of years, as early as September 21 one year in ten, and holds off past October 20 one year in ten. A hard freeze of 28°F follows 12 days later, around October 17; in spring the one-in-ten date for 28°F is May 3, 10 days before the 32°F one. The freeze-free season lasts 159 days in a typical year, shorter than at 71% of the 68 Nebraska stations; it reaches 179 days one year in ten and falls short of 139 one year in ten. On average 154 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 8 days longer, to about May 8, and return around September 29. Severe cold of 16°F or below comes every winter, usually between November 11 and March 24.

July is the warmest month at Hartington, NE, averaging 85°F by day and 63°F at night; January is the coldest at 30°F and 10°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 49% of years.

Warmth for growing adds up to 2,959 growing degree days a year (base 50°F), fewer than at 81% of the 68 Nebraska stations. 34% of them (997) have built up by the end of June, and July adds the most, 744. Precipitation totals 29.6 inches a year, most in June (4.6") and least in January (0.6"); May to September bring 64% of it.

The nearest other station, Crofton, NE, 15 miles northwest of Hartington, has the same 50% last-frost date, a first frost 3 days later (October 8), a season 1 day longer.

The first measurable snow (0.1 inch or more) in Hartington usually arrives around November 7, and the last of the season around April 5. Those are the middle dates across the winters of 1991–2020 at Hartington, NE, 0.7 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 25 days after the last snow.

ZIP 68739 is under a mile from Hartington, NE, which stands at 1,408 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 68739 in zone 5b, the band where the coldest night of the year averaged -15 to -10°F (-26.1 to -23.3°C) over 1991–2020; a zone describes winter lows, not frost dates.