Caldwell, ID 83605 Frost Dates
83605, near Caldwell, ID: the frost window
Around 04/29 is the usual last spring frost, about 244 days away. Fall's first freeze usually shows up around 10/13, roughly 164 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Caldwell 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
Caldwell's growing season runs out in roughly 7 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
Why 04/29 isn't a guarantee
04/29 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/15 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/18 and only about 1 year in 10 sees frost after that.
Caldwell against the rest of the dataset
At roughly 164 frost-free days, Caldwell places 30,826 of 40,283 ZIP codes in this dataset. Within ID, it ranks 74 of 320.
Learn more
Two guides worth reading on 83605: zone vs. frost date, on why Zone 7a and Caldwell's frost date answer different questions, and the frost range, on how to read the range around Caldwell's dates instead of trusting one.