Griswold, IA 51535 Frost Dates
When can you plant in Griswold, IA?
Around 04/23 is the usual last spring frost, about 238 days away. The first fall frost typically arrives around 10/14, about 174 frost-free days later.
Griswold sits in USDA Zone 5b (-15 to -10°F average annual minimum). The dates above are NOAA's 1991-2020 normal at the nearest reporting station, a 30-year average, not a forecast.
What to do before the first frost
About 7 weeks of growing season left in Griswold before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Griswold's last frost
04/23 is the middle of 30 years of NOAA records, not a promise. Plant by 04/10 and you're betting against frost in roughly 9 years out of 10. 05/05 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Griswold compares
About 174 days separate Griswold's last and first frost, putting it 27,555 of 40,283 ZIP codes nationally. Within IA, it ranks 194 of 1,042.
Learn more
local microclimates covers what one yard in Griswold can differ from the 51535 normal. zone vs. frost date covers why Zone 5b and Griswold's frost date answer different questions.