Boise City, ID 83702 Frost Dates
83702, near Boise City, ID: the frost window
Typically, the last spring freeze lands around 04/24, roughly 239 days out. Fall's first freeze usually shows up around 10/21, roughly 179 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Boise City in Zone 7a (0 to 5°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
Boise City's growing season runs out in roughly 8 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
04/24 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/04 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/09 and only about 1 year in 10 sees frost after that.
Boise City against the rest of the dataset
Boise City's growing season runs about 179 days, ranking 25,133 of 40,283 US ZIP codes measured here, longest to shortest. Within ID, it ranks 12 of 320.
Learn more
Two guides worth reading on 83702: the frost range, on how to read the range around Boise City's dates instead of trusting one, and local microclimates, on what one yard in Boise City can differ from the 83702 normal.