Mellette, SD 57461 Frost Dates
When can you plant in Mellette, SD?
Typically, the last spring freeze lands around 05/11, roughly 256 days out. The first fall frost typically arrives around 09/27, about 137 frost-free days later.
The USDA Plant Hardiness Zone Map puts Mellette 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
About 4 weeks of growing season left in Mellette before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 05/11 isn't a guarantee
05/11 is the middle of 30 years of NOAA records, not a promise. Plant by 04/29 and you're betting against frost in roughly 9 years out of 10. 05/23 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Mellette compares
Mellette's growing season runs about 137 days, ranking 37,589 of 40,283 US ZIP codes measured here, longest to shortest. Within SD, it ranks 345 of 378.
Learn more
local microclimates covers what one yard in Mellette can differ from the 57461 normal. zone vs. frost date covers why Zone 4a and Mellette's frost date answer different questions.