Indiana frost dates

Across Indiana, the average last spring frost is around April 24 and the average first fall frost around October 11 — roughly 170 frost-free days. USDA zones 5b, 6a, 6b.

Risk you accept	Last spring frost by	First fall frost by
Cautious (~10%)	May 8	September 27
Average (~50%)	April 24	October 11
Gambler (~90%)	April 10	October 25

→ Turn these into sowing dates with the Indiana planting calendar, or look up an exact ZIP code.

Statewide average from NOAA/NCEI freeze normals. Cautious/gambler dates are about two weeks either side of the average.