Clear Lake, SD 57226 Frost Dates
Frost dates for Clear Lake, SD, ZIP 57226
Around 05/06 is the usual last spring frost, about 251 days away. The first fall frost typically arrives around 10/01, about 145 frost-free days later.
The USDA Plant Hardiness Zone Map puts Clear Lake in Zone 4b (-25 to -20°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 4b around Clear Lake 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 Clear Lake's last frost
05/06 is the middle of 30 years of NOAA records, not a promise. Plant by 04/25 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 Clear Lake compares
About 145 days separate Clear Lake's last and first frost, putting it 36,230 of 40,283 ZIP codes nationally. Within SD, it ranks 233 of 378.
Learn more
zone vs. frost date explains why Zone 4b and Clear Lake's frost date answer different questions, and the frost range explains how to read the range around Clear Lake's dates instead of trusting one.