Castle Valley, UT 84515 Frost Dates
When can you plant in Castle Valley, UT?
The last spring frost here typically falls around 04/22, about 237 days from today. The first fall frost typically arrives around 10/20, about 179 frost-free days later.
The USDA Plant Hardiness Zone Map puts Castle Valley in Zone 6b (-5 to 0°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 8 weeks of growing season left in Castle Valley before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 04/22 isn't a guarantee
04/22 is the middle of 30 years of NOAA records, not a promise. Plant by 04/07 and you're betting against frost in roughly 9 years out of 10. 05/08 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Castle Valley compares
Castle Valley's growing season runs about 179 days, ranking 25,471 of 40,283 US ZIP codes measured here, longest to shortest. Within UT, it ranks 109 of 344.
Learn more
zone vs. frost date covers why Zone 6b and Castle Valley's frost date answer different questions. the frost range covers how to read the range around Castle Valley's dates instead of trusting one.