Frost Dates for 47923 — Brookston, Indiana

Half of springs at Chalmers 5 W, IN see their last 32°F night by April 25; only one in ten is past it by April 11, and one in ten still has one after May 11. Planting tender crops after April 30 leaves a 30% risk of a frost on them, after May 5 20%, and after May 11 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 17 in half of years, as early as October 1 one year in ten, and holds off past October 29 one year in ten. A hard freeze of 28°F follows 11 days later, around October 28; in spring the one-in-ten date for 28°F is April 28, 13 days before the 32°F one. The freeze-free season lasts 173 days in a typical year, shorter than at 77% of the 125 Indiana stations; it reaches 193 days one year in ten and falls short of 153 one year in ten. On average 134 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 10 days longer, to about May 5, and return around October 6. Severe cold of 16°F or below comes every winter, usually between November 30 and March 10.

July is the warmest month at Chalmers 5 W, IN, averaging 83°F by day and 62°F at night; January is the coldest at 31°F and 16°F. A freezing night is all but certain in every month from October 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 30% of years.

Warmth for growing adds up to 3,050 growing degree days a year (base 50°F), fewer than at 84% of the 125 Indiana stations. 36% of them (1,083) have built up by the end of June, and July adds the most, 693. Precipitation totals 41.0 inches a year, most in June (5.5") and least in February (2.1"); May to September bring 52% of it.

The nearest other station, W Lafayette 6 NW, IN, 10 miles southwest of Brookston, has a last frost 1 day later (April 26), a first frost 5 days earlier (October 12), a season 4 days shorter.

The first measurable snow (0.1 inch or more) in Brookston usually arrives around December 4, and the last of the season around March 21. Those are the middle dates across the winters of 1991–2020 at Chalmers 5 W, IN, 5.4 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 35 days after the last snow.

ZIP 47923 is 5 miles from Chalmers 5 W, IN, which stands at 720 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 47923 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.