Frost Dates for 84738 — Ivins, Utah

Half of springs at St George, UT see their last 32°F night by March 14; only one in ten is past it by February 27, and one in ten still has one after April 6. Planting tender crops after March 25 leaves a 30% risk of a frost on them, after March 31 20%, and after April 6 10%. The 23 days between the even-odds date and the one-in-ten date is wider than at 86% of the 66 Utah stations behind this site's ZIP pages, so a fixed calendar date is a gamble here.

In fall the first 32°F night comes by November 10 in half of years, as early as October 27 one year in ten, and holds off past November 22 one year in ten. A hard freeze of 28°F follows 10 days later, around November 20; in spring the one-in-ten date for 28°F is March 17, 20 days before the 32°F one. The freeze-free season lasts 239 days in a typical year, the longest of the 66 Utah stations; it reaches 260 days one year in ten and falls short of 212 one year in ten. On average 63 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 20 days longer, to about April 3, and return around November 1. Nights of 24°F, cold enough to damage hardier plants, come in 100% of winters and 16°F in 47%.

July is the warmest month at St George, UT, averaging 102°F by day and 72°F at night; December is the coldest at 53°F and 28°F. A freezing night is all but certain in every month from November to February (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, March still brings one in 85% of years and April still brings one in 18% of years.

Warmth for growing adds up to 5,546 growing degree days a year (base 50°F), the most of the 66 Utah stations. 37% of them (2,036) have built up by the end of June, and July adds the most, 1,141. Precipitation totals 9.5 inches a year, most in February (1.4") and least in June (0.2"); May to September bring 29% of it.

The nearest other station, La Verkin, UT, 23 miles east of Ivins and 337 feet higher, has a last frost 18 days later (April 1), a first frost 5 days earlier (November 5), a season 22 days shorter.

Measurable snow is rare here: only 12 of 27 winters from 1991 to 2020 recorded 0.1 inch or more at St George, UT, 4.9 miles away, so there is no typical first-snow date to plan around.

ZIP 84738 is 5 miles from St George, UT, which stands at 2,857 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 4 other ZIP codes share the station; its figures are presented in full for 84790 (St George). The 2023 USDA Plant Hardiness Zone Map lists ZIP 84738 in zone 8b, the band where the coldest night of the year averaged 15 to 20°F (-9.4 to -6.7°C) over 1991–2020; a zone describes winter lows, not frost dates.