Knoxville, IL 61448 Frost Dates
When can you plant in Knoxville, IL?
The last spring frost here typically falls around 04/21, about 236 days from today. The first fall frost typically arrives around 10/20, about 181 frost-free days later.
Knoxville 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 8 weeks of growing season left in Knoxville before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 04/21 isn't a guarantee
04/21 is the middle of 30 years of NOAA records, not a promise. Plant by 04/07 and you're betting against frost in roughly 9 years out of 10. 05/06 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Knoxville compares
Knoxville's growing season runs about 181 days, ranking 24,543 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 920 of 1,548.
Learn more
the frost range covers how to read the range around Knoxville's dates instead of trusting one. local microclimates covers what one yard in Knoxville can differ from the 61448 normal.