Rock River, WY 82083 Frost Dates
Rock River, WY: when does the frost end?
The last spring frost here typically falls around 05/22, about 267 days from today. Fall's first freeze usually shows up around 09/24, roughly 125 days after the last spring frost.
Rock River 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.
Stretching the season past the first frost
With roughly 4 weeks until Rock River's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
Why 05/22 isn't a guarantee
05/22 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/08 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 06/05 and only about 1 year in 10 sees frost after that.
Rock River against the rest of the dataset
Rock River's growing season runs about 125 days, ranking 38,814 of 40,283 US ZIP codes measured here, longest to shortest. Within WY, it ranks 81 of 192.
Learn more
Before leaning on 82083's figures: the frost range explains how to read the range around Rock River's dates instead of trusting one, while local microclimates explains what one yard in Rock River can differ from the 82083 normal.