Alton, IN 47514 Frost Dates
When can you plant in Alton, IN?
Typically, the last spring freeze lands around 04/11, roughly 226 days out. The first fall frost typically arrives around 10/26, about 197 frost-free days later.
Zone 6b (-5 to 0°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 Alton, not a forecast for this year.
What to do before the first frost
About 8 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.
How much risk comes with planting early here
04/11 is the middle of 30 years of NOAA records, not a promise. Plant by 03/27 and you're betting against frost in roughly 9 years out of 10. 04/30 is the safer bet, historically only a 1-in-10 chance of frost that late.
How Alton compares
At roughly 197 frost-free days, Alton places 18,860 of 40,283 ZIP codes in this dataset. Within IN, it ranks 160 of 927.
Learn more
local microclimates covers what one yard in Alton can differ from the 47514 normal. zone vs. frost date covers why Zone 6b and Alton's frost date answer different questions.