Jerome, ID 83338 Frost Dates
Frost dates for Jerome, ID, ZIP 83338
The last spring frost here typically falls around 05/01, about 246 days from today. The first fall frost typically arrives around 10/14, about 165 frost-free days later.
The USDA Plant Hardiness Zone Map puts Jerome in Zone 6b (-5 to 0°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
Zone 6b around Jerome has about 7 weeks left before the first fall frost — that's the usual window to get a cold frame up if you want to keep harvesting past it.
Why 05/01 isn't a guarantee
05/01 is the middle of 30 years of NOAA records, not a promise. Plant by 04/17 and you're betting against frost in roughly 9 years out of 10. 05/16 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Jerome compares
Jerome's growing season runs about 165 days, ranking 30,520 of 40,283 US ZIP codes measured here, longest to shortest. Within ID, it ranks 66 of 320.
Learn more
zone vs. frost date explains why Zone 6b and Jerome's frost date answer different questions, and the frost range explains how to read the range around Jerome's dates instead of trusting one.