Frost Dates for 62254 — Lebanon, Illinois

Half of springs at Belleville Siu Rsch, IL see their last 32°F night by April 12; only one in ten is past it by March 28, and one in ten still has one after April 28. Planting tender crops after April 19 leaves a 30% risk of a frost on them, after April 22 20%, and after April 28 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 22% of the 158 Illinois 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 3 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 16, 12 days before the 32°F one. The freeze-free season lasts 189 days in a typical year, longer than at 62% of the 158 Illinois stations; it reaches 209 days one year in ten and falls short of 167 one year in ten. On average 93 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 April 23, and return around October 9. Severe cold of 16°F or below comes every winter, usually between December 4 and February 28.

July is the warmest month at Belleville Siu Rsch, IL, averaging 90°F by day and 68°F at night; January is the coldest at 43°F and 24°F. A freezing night is all but certain in every month from November to March (a 90% chance or more). From May to September the chance of a 32°F night stays under 10% each month. In spring, April still brings one in 81% of years.

Warmth for growing adds up to 4,520 growing degree days a year (base 50°F), more than at 99% of the 158 Illinois stations. 39% of them (1,745) have built up by the end of June, and July adds the most, 899. Precipitation totals 43.4 inches a year, most in May (5.1") and least in February (2.2"); May to September bring 48% of it.

The nearest other station, Cahokia St Louis Airport, IL, 19 miles west of Lebanon, has a last frost 4 days earlier (April 8), a first frost 6 days later (October 26), a season 11 days longer.

The first measurable snow (0.1 inch or more) in Lebanon usually arrives around December 14, and the last of the season around February 27. Those are the middle dates across the winters of 1991–2020 at Belleville Siu Rsch, IL, 5.9 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 44 days after the last snow.

ZIP 62254 is 6 miles from Belleville Siu Rsch, IL, which stands at 450 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 15 other ZIP codes share the station; its figures are presented in full for 62269 (O Fallon). The 2023 USDA Plant Hardiness Zone Map lists ZIP 62254 in zone 6b, the band where the coldest night of the year averaged -5 to 0°F (-20.6 to -17.8°C) over 1991–2020; a zone describes winter lows, not frost dates.