Frost Dates for 84339 — Wellsville, Utah

Half of springs at Logan 5 SW Exp Farm, UT see their last 32°F night by May 12; only one in ten is past it by April 30, and one in ten still has one after May 29. Planting tender crops after May 18 leaves a 30% risk of a frost on them, after May 22 20%, and after May 29 10%. The 17 days between the even-odds date and the one-in-ten date is narrower than at 68% of the 66 Utah 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 14 one year in ten, and holds off past October 12 one year in ten. A hard freeze of 28°F follows 11 days later, around October 9; in spring the one-in-ten date for 28°F is May 12, 17 days before the 32°F one. The freeze-free season lasts 138 days in a typical year, shorter than at 62% of the 66 Utah stations; it reaches 157 days one year in ten and falls short of 117 one year in ten. On average 175 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 19 days longer, to about May 31, and return around September 18. Severe cold of 16°F or below comes every winter, usually between November 16 and March 9.

July is the warmest month at Logan 5 SW Exp Farm, UT, averaging 88°F by day and 55°F at night; January is the coldest at 32°F and 13°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 87% of years.

Warmth for growing adds up to 2,208 growing degree days a year (base 50°F), fewer than at 74% of the 66 Utah stations. 27% of them (589) have built up by the end of June, and July adds the most, 652. Precipitation totals 17.9 inches a year, most in May (2.2") and least in July (0.6"); May to September bring 32% of it.

The nearest other station, Logan Utah St Univ, UT, 10 miles northeast of Wellsville and 302 feet higher, has a last frost 12 days earlier (April 30), a first frost 18 days later (October 16), a season 28 days longer.

The first measurable snow (0.1 inch or more) in Wellsville usually arrives around November 3, and the last of the season around April 14. Those are the middle dates across the winters of 1991–2020 at Logan 5 SW Exp Farm, UT, 2.5 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 84339 is 3 miles from Logan 5 SW Exp Farm, UT, which stands at 4,488 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station; its figures are presented in full for 84319 (Hyrum). The 2023 USDA Plant Hardiness Zone Map lists ZIP 84339 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.