Frost Dates for 46773 — Monroeville, Indiana

Half of springs at Decatur 1 N, IN see their last 32°F night by April 23; only one in ten is past it by April 7, and one in ten still has one after May 8. Planting tender crops after April 30 leaves a 30% risk of a frost on them, after May 3 20%, and after May 8 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 70% of the 125 Indiana stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 19 in half of years, as early as October 5 one year in ten, and holds off past November 1 one year in ten. A hard freeze of 28°F follows 12 days later, around October 31; in spring the one-in-ten date for 28°F is April 28, 10 days before the 32°F one. The freeze-free season lasts 178 days in a typical year, shorter than at 62% of the 125 Indiana stations; it reaches 199 days one year in ten and falls short of 156 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 December 5 and March 11.

July is the warmest month at Decatur 1 N, IN, averaging 84°F by day and 63°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 3,135 growing degree days a year (base 50°F), fewer than at 68% of the 125 Indiana stations. 35% of them (1,112) have built up by the end of June, and July adds the most, 721. Precipitation totals 40.7 inches a year, most in May (4.8") and least in February (2.1"); May to September bring 51% of it.

The nearest other station, Woodburn 3N, IN, 12 miles north of Monroeville, has a last frost 4 days later (April 27), the same first-frost date, a season 4 days shorter.

The first measurable snow (0.1 inch or more) in Monroeville usually arrives around December 1, and the last of the season around March 25. Those are the middle dates across the winters of 1991–2020 at Decatur 1 N, IN, 10.2 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 29 days after the last snow.

ZIP 46773 is 10 miles from Decatur 1 N, IN, which stands at 785 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 46733 (Decatur). The 2023 USDA Plant Hardiness Zone Map lists ZIP 46773 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.