Clear Lake, IA 50428 Frost Dates
When can you plant in Clear Lake, IA?
Typically, the last spring freeze lands around 05/03, roughly 248 days out. The first fall frost typically arrives around 10/01, about 150 frost-free days later.
Clear Lake 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 5 weeks of growing season left in Clear Lake before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Clear Lake's last frost
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. 05/15 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Clear Lake compares
About 150 days separate Clear Lake's last and first frost, putting it 35,267 of 40,283 ZIP codes nationally. Within IA, it ranks 998 of 1,042.
Learn more
local microclimates covers what one yard in Clear Lake can differ from the 50428 normal. zone vs. frost date covers why Zone 5a and Clear Lake's frost date answer different questions.