Herrin, IL 62841 Frost Dates
When can you plant in Herrin, IL?
Around 04/09 is the usual last spring frost, about 224 days away. The first fall frost typically arrives around 10/22, about 195 frost-free days later.
Zone 7a (0 to 5°F average annual minimum) comes from the USDA Plant Hardiness Zone Map; the frost dates above are the 1991-2020 normal at the nearest reporting NOAA station for Herrin, not a forecast for this year.
What to do before the first frost
About 8 weeks of growing season left in Herrin before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
Why 04/09 isn't a guarantee
04/09 is the middle of 30 years of NOAA records, not a promise. Plant by 03/25 and you're betting against frost in roughly 9 years out of 10. 04/25 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Herrin compares
Herrin's growing season runs about 195 days, ranking 19,220 of 40,283 US ZIP codes measured here, longest to shortest. Within IL, it ranks 334 of 1,548.
Learn more
local microclimates covers what one yard in Herrin can differ from the 62841 normal. zone vs. frost date covers why Zone 7a and Herrin's frost date answer different questions.