Irene, SD 57037 Frost Dates
Frost dates for Irene, SD, ZIP 57037
Around 04/27 is the usual last spring frost, about 242 days away. The first fall frost typically arrives around 10/11, about 164 frost-free days later.
Zone 5a (-20 to -15°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 Irene, not a forecast for this year.
What to do before the first frost
Zone 5a around Irene 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.
Why 04/27 isn't a guarantee
04/27 is the middle of 30 years of NOAA records, not a promise. Plant by 04/13 and you're betting against frost in roughly 9 years out of 10. 05/10 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Irene compares
Irene's growing season runs about 164 days, ranking 31,139 of 40,283 US ZIP codes measured here, longest to shortest. Within SD, it ranks 15 of 378.
Learn more
local microclimates explains what one yard in Irene can differ from the 57037 normal, and zone vs. frost date explains why Zone 5a and Irene's frost date answer different questions.