Indianapolis, IN 46230 Frost Dates
46230, near Indianapolis, IN: the frost window
Around 04/20 is the usual last spring frost, about 235 days away. Fall's first freeze usually shows up around 10/21, roughly 183 days after the last spring frost.
The USDA Plant Hardiness Zone Map puts Indianapolis in Zone 6b (-5 to 0°F average annual minimum); frost dates are NOAA's 1991-2020 station normal, not this year's forecast.
Stretching the season past the first frost
Indianapolis's growing season runs out in roughly 8 weeks — a cold frame or greenhouse kit is the usual way to keep cool-weather crops going past the first frost.
How much risk comes with planting early here
04/20 is the middle of 30 years of NOAA records, not a promise. Getting tender plants in by 04/06 carries real risk, frost has hit that late in about 9 of 10 years here. Wait until 05/05 and only about 1 year in 10 sees frost after that.
Indianapolis against the rest of the dataset
At roughly 183 frost-free days, Indianapolis places 23,708 of 40,283 ZIP codes in this dataset. Within IN, it ranks 400 of 927.
Learn more
Two guides worth reading on 46230: local microclimates, on what one yard in Indianapolis can differ from the 46230 normal, and zone vs. frost date, on why Zone 6b and Indianapolis's frost date answer different questions.