McLaughlin, SD 57621 Frost Dates
Frost dates for McLaughlin, SD, ZIP 57621
Around 05/09 is the usual last spring frost, about 254 days away. The first fall frost typically arrives around 09/30, about 143 frost-free days later.
Zone 4b (-25 to -20°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for McLaughlin, not a forecast for this year.
What to do before the first frost
Zone 4b around McLaughlin 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 McLaughlin's last frost
05/09 is the middle of 30 years of NOAA records, not a promise. Plant by 04/28 and you're betting against frost in roughly 9 years out of 10. 05/24 is the safer bet, historically only a 1-in-10 chance of frost that late.
How McLaughlin compares
At roughly 143 frost-free days, McLaughlin places 36,589 of 40,283 ZIP codes in this dataset. Within SD, it ranks 268 of 378.
Learn more
local microclimates explains what one yard in McLaughlin can differ from the 57621 normal, and zone vs. frost date explains why Zone 4b and McLaughlin's frost date answer different questions.