Gillette, WY 82727 Frost Dates
When can you plant in Gillette, WY?
Typically, the last spring freeze lands around 05/15, roughly 260 days out. The first fall frost typically arrives around 10/01, about 136 frost-free days later.
Gillette sits in USDA Zone 4b (-25 to -20°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
What to do before the first frost
About 5 weeks of growing season left in Gillette before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 05/15 isn't a guarantee
05/15 is the middle of 30 years of NOAA records, not a promise. Plant by 05/01 and you're betting against frost in roughly 9 years out of 10. 05/27 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Gillette compares
Gillette's growing season runs about 136 days, ranking 37,623 of 40,283 US ZIP codes measured here, longest to shortest. Within WY, it ranks 43 of 192.
Learn more
zone vs. frost date covers why Zone 4b and Gillette's frost date answer different questions. the frost range covers how to read the range around Gillette's dates instead of trusting one.