Lebanon, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Lebanon, a city in St. Clair County, Illinois.
Today
97°F
Partly Sunny
Partly sunny, with a high near 97. Heat index values as high as 100. Southwest wind around 7 mph.
7-day forecast for Lebanon
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Today | 97°F | Partly Sunny | 7 mph SW | 3% |
| Tonight | 73°F | Partly Cloudy | 5 mph S | 3% |
| Sunday | 93°F | Slight Chance Rain Showers then Slight Chance Showers And Thunderstorms | 2 to 7 mph W | 21% |
| Sunday Night | 67°F | Showers And Thunderstorms Likely | 5 to 9 mph NE | 56% |
| Monday | 79°F | Showers And Thunderstorms Likely | 5 to 12 mph NE | 64% |
| Monday Night | 59°F | Showers And Thunderstorms Likely | 6 to 12 mph NE | 57% |
| Tuesday | 72°F | Slight Chance Rain Showers then Partly Sunny | 9 to 13 mph N | 19% |
| Tuesday Night | 54°F | Mostly Cloudy | 5 to 13 mph N | 7% |
| Wednesday | 74°F | Mostly Sunny | 7 to 10 mph N | 2% |
| Wednesday Night | 55°F | Partly Cloudy | 2 to 9 mph N | 0% |
| Thursday | 76°F | Mostly Sunny | 2 to 9 mph N | 1% |
| Thursday Night | 57°F | Partly Cloudy | 2 to 8 mph NE | 3% |
| Friday | 78°F | Mostly Sunny | 2 to 8 mph NE | 5% |
| Friday Night | 57°F | Partly Cloudy | 2 to 7 mph NE | 5% |
Forecast source: National Weather Service (api.weather.gov) for Lebanon (38.601, -89.810). Updated through the day.
Growing snapshot for Lebanon
Last spring frost
Apr 12
First fall frost
Oct 20
Growing season
189 days
Hardiness zone
6b
More local growing data for Lebanon: nearby ZIP 62254 weather · frost dates · planting calendar · Illinois frost dates
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New Athens
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Rentchler
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St. Libory
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Climate data from the nearest NOAA station, Belleville Siu Rsch, Il (6.3 mi from Lebanon). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.