St. George, UT 84790 Frost Dates
Frost dates for St. George, UT, ZIP 84790
Typically, the last spring freeze lands around 03/14, roughly 198 days out. The first fall frost typically arrives around 11/10, about 239 frost-free days later.
The USDA Plant Hardiness Zone Map puts St. George in Zone 8b (15 to 20°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 8b around St. George has about 11 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
How much risk comes with planting early here
03/14 is the middle of 30 years of NOAA records, not a promise. Plant by 02/27 and you're betting against frost in roughly 9 years out of 10. 04/06 is the safer bet, historically only a 1-in-10 chance of frost that late.
How St. George compares
About 239 days separate St. George's last and first frost, putting it 8,753 of 40,283 ZIP codes nationally. Within UT, it ranks 3 of 344.
Learn more
local microclimates explains what one yard in St. George can differ from the 84790 normal, and zone vs. frost date explains why Zone 8b and St. George's frost date answer different questions.