St. Anthony, ID 83421 Frost Dates
When can you plant in St. Anthony, ID?
Typically, the last spring freeze lands around 05/21, roughly 266 days out. The first fall frost typically arrives around 09/21, about 121 frost-free days later.
The USDA Plant Hardiness Zone Map puts St. Anthony in Zone 5a (-20 to -15°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
About 3 weeks of growing season left in St. Anthony before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around St. Anthony's last frost
05/21 is the middle of 30 years of NOAA records, not a promise. Plant by 05/04 and you're betting against frost in roughly 9 years out of 10. 06/13 is the safer bet, historically only a 1-in-10 chance of frost that late.
How St. Anthony compares
St. Anthony's growing season runs about 121 days, ranking 39,004 of 40,283 US ZIP codes measured here, longest to shortest. Within ID, it ranks 203 of 320.
Learn more
the frost range covers how to read the range around St. Anthony's dates instead of trusting one. local microclimates covers what one yard in St. Anthony can differ from the 83421 normal.