Tolley, ND 58787 Frost Dates
Frost dates for Tolley, ND, ZIP 58787
Typically, the last spring freeze lands around 05/17, roughly 262 days out. The first fall frost typically arrives around 09/23, about 127 frost-free days later.
Tolley sits in USDA Zone 4a (-30 to -25°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.
What to do before the first frost
Zone 4a around Tolley has about 4 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 05/17 isn't a guarantee
05/17 is the middle of 30 years of NOAA records, not a promise. Plant by 05/06 and you're betting against frost in roughly 9 years out of 10. 05/30 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Tolley compares
About 127 days separate Tolley's last and first frost, putting it 38,671 of 40,283 ZIP codes nationally. Within ND, it ranks 349 of 405.
Learn more
local microclimates explains what one yard in Tolley can differ from the 58787 normal, and zone vs. frost date explains why Zone 4a and Tolley's frost date answer different questions.