Frost Dates for 47374 — Richmond, Indiana

Half of springs at Richmond Wtr Wks, IN see their last 32°F night by April 24; only one in ten is past it by April 8, and one in ten still has one after May 10. Planting tender crops after April 30 leaves a 30% risk of a frost on them, after May 5 20%, and after May 10 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 20 in half of years, as early as October 7 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 10 days later, around October 30; in spring the one-in-ten date for 28°F is April 28, 12 days before the 32°F one. The freeze-free season lasts 180 days in a typical year, shorter than at 54% of the 125 Indiana stations; it reaches 200 days one year in ten and falls short of 159 one year in ten. On average 117 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 9 days longer, to about May 3, and return around October 10. Severe cold of 16°F or below comes every winter, usually between December 4 and March 9.

July is the warmest month at Richmond Wtr Wks, 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 30% of years.

Warmth for growing adds up to 3,399 growing degree days a year (base 50°F), more than at 53% of the 125 Indiana stations. 36% of them (1,236) have built up by the end of June, and July adds the most, 749. Precipitation totals 42.9 inches a year, most in June (4.8") and least in February (2.3"); May to September bring 47% of it.

The nearest other station, Eaton, OH, 15 miles southeast of Richmond, has a last frost 1 day later (April 25), the same first-frost date, a season 4 days shorter.

The first measurable snow (0.1 inch or more) in Richmond usually arrives around December 7, and the last of the season around March 12. Those are the middle dates across the winters of 1991–2020 at Richmond Wtr Wks, IN, 1.8 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 47374 is 2 miles from Richmond Wtr Wks, IN, which stands at 1,005 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 3 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 47374 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.