Crystal Lake, IA 50432 Frost Dates
When can you plant in Crystal Lake, IA?
The last spring frost here typically falls around 05/03, about 248 days from today. The first fall frost typically arrives around 10/01, about 150 frost-free days later.
Crystal 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 Crystal Lake 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. 05/15 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Crystal Lake compares
About 150 days separate Crystal Lake's last and first frost, putting it 35,421 of 40,283 ZIP codes nationally. Within IA, it ranks 1,016 of 1,042.
Learn more
zone vs. frost date covers why Zone 5a and Crystal Lake's frost date answer different questions. the frost range covers how to read the range around Crystal Lake's dates instead of trusting one.