Frost Dates for 46176 — Shelbyville, Indiana

Half of springs at Shelbyville Sewage Plt, IN see their last 32°F night by April 17; only one in ten is past it by April 3, and one in ten still has one after May 3. Planting tender crops after April 23 leaves a 30% risk of a frost on them, after April 28 20%, and after May 3 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 35% of the 125 Indiana stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 22 in half of years, as early as October 9 one year in ten, and holds off past November 4 one year in ten. A hard freeze of 28°F follows 10 days later, around November 1; in spring the one-in-ten date for 28°F is April 22, 11 days before the 32°F one. The freeze-free season lasts 187 days in a typical year, longer than at 66% of the 125 Indiana stations; it reaches 206 days one year in ten and falls short of 167 one year in ten. On average 115 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 11 days longer, to about April 28, and return around October 12. Severe cold of 16°F or below comes every winter, usually between December 7 and March 5.

July is the warmest month at Shelbyville Sewage Plt, IN, averaging 85°F by day and 64°F at night; January is the coldest at 36°F and 20°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 15% of years.

Warmth for growing adds up to 3,497 growing degree days a year (base 50°F), more than at 61% of the 125 Indiana stations. 37% of them (1,277) have built up by the end of June, and July adds the most, 756. Precipitation totals 44.1 inches a year, most in June (4.9") and least in February (2.7"); May to September bring 46% of it.

The nearest other station, Shelbyville Municipal Airport, IN, 4 miles northwest of Shelbyville, has a last frost 3 days earlier (April 14), a first frost 1 day later (October 23), a season 4 days longer.

The first measurable snow (0.1 inch or more) in Shelbyville usually arrives around December 18, and the last of the season around March 4. Those are the middle dates across the winters of 1991–2020 at Shelbyville Sewage Plt, IN, 1.1 miles away: half of years saw snow earlier, half later. Snow fell in 80% of those winters. The last 32°F night of spring typically comes 44 days after the last snow.

ZIP 46176 is 1 mile from Shelbyville Sewage Plt, IN, which stands at 752 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 46176 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.