Idaho City, ID 83631 Frost Dates
Idaho City, ID: when does the frost end?
Around 06/17 is the usual last spring frost, about 293 days away. Fall's first freeze usually shows up around 09/05, roughly 80 days after the last spring frost.
Idaho City sits in USDA Zone 6b (-5 to 0°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 1 week until Idaho City's first fall frost, a row cover or cold frame is what stretches the last few weeks of harvest here.
The actual range around Idaho City's last frost
06/17 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 05/30 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 07/04 and only about 1 year in 10 sees frost after that.
Idaho City against the rest of the dataset
About 80 days separate Idaho City's last and first frost, putting it 40,053 of 40,283 ZIP codes nationally. Within ID, it ranks 284 of 320.
Learn more
Before leaning on 83631's figures: zone vs. frost date explains why Zone 6b and Idaho City's frost date answer different questions, while the frost range explains how to read the range around Idaho City's dates instead of trusting one.