Sullivan, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Sullivan, a city in Moultrie County, Illinois.
Tonight
43°F
Slight Chance Drizzle then Mostly Cloudy
A slight chance of drizzle before 10pm. Mostly cloudy, with a low around 43. Southwest wind around 8 mph.
7-day forecast for Sullivan
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Tonight | 43°F | Slight Chance Drizzle then Mostly Cloudy | 8 mph SW | 10% |
| Thursday | 59°F | Partly Sunny | 7 to 13 mph WSW | 9% |
| Thursday Night | 40°F | Mostly Cloudy | 5 to 8 mph NW | 12% |
| Friday | 52°F | Partly Sunny | 8 to 12 mph N | 1% |
| Friday Night | 30°F | Mostly Clear | 2 to 6 mph NNW | 0% |
| Saturday | 53°F | Sunny | 2 to 6 mph NNW | 0% |
| Saturday Night | 29°F | Mostly Clear | 2 mph NW | 0% |
| Sunday | 59°F | Sunny | 2 to 7 mph W | 0% |
| Sunday Night | 32°F | Mostly Clear | 3 mph W | 0% |
| Monday | 64°F | Sunny | 1 to 7 mph WSW | 0% |
| Monday Night | 36°F | Clear | 5 mph WSW | 0% |
| Tuesday | 65°F | Sunny | 5 mph W | 2% |
| Tuesday Night | 37°F | Mostly Clear | 3 mph NW | 2% |
| Veterans Day | 65°F | Sunny | 5 mph N | 2% |
Forecast source: National Weather Service (api.weather.gov) for Sullivan (39.595, -88.609). Updated through the day.
Growing snapshot for Sullivan
Last spring frost
Apr 15
First fall frost
Oct 22
Growing season
187 days
Hardiness zone
6a
More local growing data for Sullivan: nearby ZIP 61951 weather · frost dates · planting calendar · Illinois frost dates
Nearby towns & communities
Climate data from the nearest NOAA station, Sullivan 3S, Il (2.6 mi from Sullivan). Frost dates are 1991–2020 averages, not a forecast. Page updated Nov 5, 2026.