Sullivan, IL Weather & Growing Conditions
Overnight
69°F
Partly Cloudy
Partly cloudy, with a low around 69. Southeast wind around 7 mph.
7-day forecast
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 69°F | Partly Cloudy | 7 mph SE | 4% |
| Saturday | 92°F | Chance Showers And Thunderstorms | 6 to 9 mph SSW | 30% |
| Saturday Night | 70°F | Mostly Cloudy then Slight Chance Showers And Thunderstorms | 5 to 8 mph S | 15% |
| Sunday | 88°F | Chance Showers And Thunderstorms | 3 to 9 mph NW | 29% |
| Sunday Night | 61°F | Showers And Thunderstorms Likely | 10 mph NE | 60% |
| Monday | 74°F | Showers And Thunderstorms Likely | 12 mph NE | 64% |
| Monday Night | 55°F | Showers And Thunderstorms Likely | 9 to 13 mph NE | 60% |
| Tuesday | 70°F | Chance Showers And Thunderstorms then Mostly Cloudy | 13 mph NE | 32% |
| Tuesday Night | 52°F | Mostly Cloudy | 6 to 12 mph NNE | 8% |
| Wednesday | 72°F | Partly Sunny | 7 to 10 mph NNE | 2% |
| Wednesday Night | 52°F | Partly Cloudy | 3 to 9 mph NNE | 2% |
| Thursday | 74°F | Mostly Sunny | 5 to 9 mph NNE | 3% |
| Thursday Night | 54°F | Partly Cloudy | 3 to 7 mph NNE | 4% |
| Friday | 75°F | Mostly Sunny | 5 to 9 mph NNE | 4% |
Forecast source: National Weather Service (api.weather.gov). Updated through the day.
Growing snapshot for Sullivan, IL
Last spring frost
Apr 15
First fall frost
Oct 22
Growing season
187 days
Hardiness zone
6a
Explore more for Sullivan, IL: full frost dates · planting calendar · Illinois frost dates
Climate data from the nearest NOAA station, Sullivan 3S, Il (2.6 mi). Frost dates are 1991–2020 averages, not a forecast. Page updated Sep 19, 2026.