Ossian, IA 52161 Frost Dates
When can you plant in Ossian, IA?
Around 05/03 is the usual last spring frost, about 248 days away. The first fall frost typically arrives around 10/07, about 157 frost-free days later.
Ossian sits in USDA Zone 5a (-20 to -15°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 6 weeks of growing season left in Ossian 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
05/03 is the middle of 30 years of NOAA records, not a promise. Plant by 04/19 and you're betting against frost in roughly 9 years out of 10. 05/16 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Ossian compares
At roughly 157 frost-free days, Ossian places 33,400 of 40,283 ZIP codes in this dataset. Within IA, it ranks 843 of 1,042.
Learn more
local microclimates covers what one yard in Ossian can differ from the 52161 normal. zone vs. frost date covers why Zone 5a and Ossian's frost date answer different questions.