Hanna, WY 82327 Frost Dates
When can you plant in Hanna, WY?
Typically, the last spring freeze lands around 05/20, roughly 265 days out. The first fall frost typically arrives around 09/28, about 128 frost-free days later.
Hanna 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 4 weeks of growing season left in Hanna before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 05/20 isn't a guarantee
05/20 is the middle of 30 years of NOAA records, not a promise. Plant by 05/03 and you're betting against frost in roughly 9 years out of 10. 06/13 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Hanna compares
Hanna's growing season runs about 128 days, ranking 38,568 of 40,283 US ZIP codes measured here, longest to shortest. Within WY, it ranks 70 of 192.
Learn more
the frost range covers how to read the range around Hanna's dates instead of trusting one. local microclimates covers what one yard in Hanna can differ from the 82327 normal.