Frost Dates for 46740 — Geneva, Indiana

Half of springs at Berne Wwtp, IN see their last 32°F night by April 23; only one in ten is past it by April 9, and one in ten still has one after May 7. Planting tender crops after April 30 leaves a 30% risk of a frost on them, after May 2 20%, and after May 7 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 89% 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 11 days later, around November 2; in spring the one-in-ten date for 28°F is April 29, 8 days before the 32°F one. The freeze-free season lasts 181 days in a typical year, shorter than at 50% of the 125 Indiana stations; it reaches 201 days one year in ten and falls short of 162 one year in ten. On average 121 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 8 days longer, to about May 1, and return around October 11. Severe cold of 16°F or below comes every winter, usually between December 5 and March 14.

July is the warmest month at Berne Wwtp, IN, averaging 84°F by day and 64°F at night; January is the coldest at 33°F and 18°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 27% of years.

Warmth for growing adds up to 3,216 growing degree days a year (base 50°F), fewer than at 62% of the 125 Indiana stations. 35% of them (1,127) have built up by the end of June, and July adds the most, 741. Precipitation totals 42.0 inches a year, most in May (4.6") and least in February (2.4"); May to September bring 50% of it.

The nearest other station, Portland 1 SW, IN, 13 miles south of Geneva, has a last frost 5 days later (April 28), a first frost 7 days earlier (October 15), a season 10 days shorter.

The first measurable snow (0.1 inch or more) in Geneva usually arrives around November 27, and the last of the season around March 20. Those are the middle dates across the winters of 1991–2020 at Berne Wwtp, IN, 5.1 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 34 days after the last snow.

ZIP 46740 is 5 miles from Berne Wwtp, IN, which stands at 839 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station; its figures are presented in full for 46711 (Berne). The 2023 USDA Plant Hardiness Zone Map lists ZIP 46740 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.