Delmont, SD 57330 Frost Dates
Frost dates for Delmont, SD, ZIP 57330
Typically, the last spring freeze lands around 04/29, roughly 244 days out. The first fall frost typically arrives around 10/09, about 164 frost-free days later.
The USDA Plant Hardiness Zone Map puts Delmont 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
Zone 5a around Delmont has about 6 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.
The actual range around Delmont's last frost
04/29 is the middle of 30 years of NOAA records, not a promise. Plant by 04/12 and you're betting against frost in roughly 9 years out of 10. 05/12 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Delmont compares
At roughly 164 frost-free days, Delmont places 31,223 of 40,283 ZIP codes in this dataset. Within SD, it ranks 19 of 378.
Learn more
the frost range explains how to read the range around Delmont's dates instead of trusting one, and local microclimates explains what one yard in Delmont can differ from the 57330 normal.