Keystone, IA 52249 Frost Dates
When can you plant in Keystone, IA?
Typically, the last spring freeze lands around 04/28, roughly 243 days out. The first fall frost typically arrives around 10/10, about 165 frost-free days later.
The USDA Plant Hardiness Zone Map puts Keystone in Zone 5a (-20 to -15°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 6 weeks of growing season left in Keystone before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
How much risk comes with planting early here
04/28 is the middle of 30 years of NOAA records, not a promise. Plant by 04/14 and you're betting against frost in roughly 9 years out of 10. 05/11 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Keystone compares
At roughly 165 frost-free days, Keystone places 30,683 of 40,283 ZIP codes in this dataset. Within IA, it ranks 531 of 1,042.
Learn more
the frost range covers how to read the range around Keystone's dates instead of trusting one. local microclimates covers what one yard in Keystone can differ from the 52249 normal.