Frost Dates for 47403 — Bloomington, Indiana

Half of springs at Bloomington Monroe Co Airport, 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 5. Planting tender crops after April 24 leaves a 30% risk of a frost on them, after April 28 20%, and after May 5 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 84% 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 8 one year in ten, and holds off past November 2 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 21, 14 days before the 32°F one. The freeze-free season lasts 185 days in a typical year, longer than at 58% of the 125 Indiana stations; it reaches 205 days one year in ten and falls short of 163 one year in ten. On average 108 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 13 days longer, to about April 30, and return around October 11. Severe cold of 16°F or below comes every winter, usually between December 4 and March 3.

July is the warmest month at Bloomington Monroe Co Airport, IN, averaging 85°F by day and 64°F at night; January is the coldest at 39°F and 22°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 16% of years.

Warmth for growing adds up to 3,622 growing degree days a year (base 50°F), more than at 64% of the 125 Indiana stations. 38% of them (1,366) have built up by the end of June, and July adds the most, 764. Precipitation totals 46.9 inches a year, most in June (5.1") and least in February (2.7"); May to September bring 46% of it.

The nearest other station, Bloomington Indiana Univ, IN, 5 miles northeast of Bloomington, has a last frost 2 days earlier (April 15), a first frost 4 days later (October 26), a season 7 days longer.

The first measurable snow (0.1 inch or more) in Bloomington usually arrives around December 9, and the last of the season around March 5. Those are the middle dates across the winters of 1991–2020 at Bloomington Indiana Univ, IN, 4.6 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 43 days after the last snow.

ZIP 47403 is 2 miles from Bloomington Monroe Co Airport, IN, which stands at 844 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 47403 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.