Britton, SD 57430 Frost Dates
Frost dates for Britton, SD, ZIP 57430
Around 05/07 is the usual last spring frost, about 252 days away. The first fall frost typically arrives around 10/01, about 146 frost-free days later.
The USDA Plant Hardiness Zone Map puts Britton in Zone 4a (-30 to -25°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 4a around Britton has about 5 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 Britton's last frost
05/07 is the middle of 30 years of NOAA records, not a promise. Plant by 04/24 and you're betting against frost in roughly 9 years out of 10. 05/20 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Britton compares
At roughly 146 frost-free days, Britton places 36,063 of 40,283 ZIP codes in this dataset. Within SD, it ranks 215 of 378.
Learn more
the frost range explains how to read the range around Britton's dates instead of trusting one, and local microclimates explains what one yard in Britton can differ from the 57430 normal.