Frost Dates for 47978 — Rensselaer, Indiana

Half of springs at Rensselaer, 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 29 leaves a 30% risk of a frost on them, after May 1 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 18 in half of years, as early as October 4 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 11 days later, around October 29; in spring the one-in-ten date for 28°F is April 27, 10 days before the 32°F one. The freeze-free season lasts 177 days in a typical year, shorter than at 66% of the 125 Indiana stations; it reaches 197 days one year in ten and falls short of 157 one year in ten. On average 127 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 May 4, and return around October 7. Severe cold of 16°F or below comes every winter, usually between November 30 and March 9.

July is the warmest month at Rensselaer, IN, averaging 84°F by day and 63°F at night; January is the coldest at 32°F and 16°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 23% of years.

Warmth for growing adds up to 3,213 growing degree days a year (base 50°F), fewer than at 63% of the 125 Indiana stations. 36% of them (1,147) have built up by the end of June, and July adds the most, 733. Precipitation totals 40.1 inches a year, most in June (4.8") and least in February (2.0"); May to September bring 52% of it.

The nearest other station, Francesville, IN, 13 miles east of Rensselaer, has a last frost 3 days later (April 26), a first frost 1 day earlier (October 17), a season 4 days shorter.

The first measurable snow (0.1 inch or more) in Rensselaer usually arrives around December 1, and the last of the season around March 18. Those are the middle dates across the winters of 1991–2020 at Rensselaer, IN, 3.4 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 36 days after the last snow.

ZIP 47978 is 3 miles from Rensselaer, IN, which stands at 630 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 47978 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.