Lyman, WY 82937 Frost Dates
When can you plant in Lyman, WY?
The last spring frost here typically falls around 06/14, about 290 days from today. The first fall frost typically arrives around 09/09, about 84 frost-free days later.
Lyman sits in USDA Zone 5a (-20 to -15°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 2 weeks of growing season left in Lyman before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 06/14 isn't a guarantee
06/14 is the middle of 30 years of NOAA records, not a promise. Plant by 05/31 and you're betting against frost in roughly 9 years out of 10. 07/01 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Lyman compares
About 84 days separate Lyman's last and first frost, putting it 39,997 of 40,283 ZIP codes nationally. Within WY, it ranks 148 of 192.
Learn more
zone vs. frost date covers why Zone 5a and Lyman's frost date answer different questions. the frost range covers how to read the range around Lyman's dates instead of trusting one.