Koosharem, UT 84732 Frost Dates
When can you plant in Koosharem, UT?
Typically, the last spring freeze lands around 06/06, roughly 282 days out. The first fall frost typically arrives around 09/21, about 104 frost-free days later.
The USDA Plant Hardiness Zone Map puts Koosharem in Zone 5b (-15 to -10°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
About 3 weeks of growing season left in Koosharem before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 06/06 isn't a guarantee
06/06 is the middle of 30 years of NOAA records, not a promise. Plant by 05/24 and you're betting against frost in roughly 9 years out of 10. 06/26 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Koosharem compares
Koosharem's growing season runs about 104 days, ranking 39,615 of 40,283 US ZIP codes measured here, longest to shortest. Within UT, it ranks 329 of 344.
Learn more
zone vs. frost date covers why Zone 5b and Koosharem's frost date answer different questions. the frost range covers how to read the range around Koosharem's dates instead of trusting one.