Alton, IN 47525 Frost Dates
When can you plant in Alton, IN?
Typically, the last spring freeze lands around 04/02, roughly 217 days out. The first fall frost typically arrives around 11/07, about 218 frost-free days later.
The USDA Plant Hardiness Zone Map puts Alton in Zone 7a (0 to 5°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
What to do before the first frost
About 10 weeks of growing season left in Alton before the first fall frost — a cold frame or row cover can stretch harvest weeks past that date.
The actual range around Alton's last frost
04/02 is the middle of 30 years of NOAA records, not a promise. Plant by 03/16 and you're betting against frost in roughly 9 years out of 10. 04/20 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Alton compares
At roughly 218 frost-free days, Alton places 13,361 of 40,283 ZIP codes in this dataset. Within IN, it ranks 27 of 927.
Learn more
local microclimates covers what one yard in Alton can differ from the 47525 normal. zone vs. frost date covers why Zone 7a and Alton's frost date answer different questions.