Sullivan, IL Weather & Growing Conditions
Local forecast, frost dates, hardiness zone and planting guidance for Sullivan, a city in Moultrie County, Illinois.
Overnight
61°F
Patchy Fog
Patchy fog. Clear, with a low around 61. Southeast wind around 3 mph.
7-day forecast for Sullivan
| When | Temp | Forecast | Wind | Precip |
|---|---|---|---|---|
| Overnight | 61°F | Patchy Fog | 3 mph SE | 0% |
| Tuesday | 86°F | Patchy Fog then Sunny | 5 mph SSE | 0% |
| Tuesday Night | 65°F | Mostly Clear | 3 mph SSE | 0% |
| Wednesday | 86°F | Sunny | 6 mph S | 2% |
| Wednesday Night | 67°F | Slight Chance Showers And Thunderstorms | 6 mph S | 52% |
| Thursday | 83°F | Showers And Thunderstorms | 3 to 7 mph SSW | 76% |
| Thursday Night | 66°F | Chance Showers And Thunderstorms | 5 mph S | 29% |
| Friday | 84°F | Slight Chance Showers And Thunderstorms | 5 mph SSW | 17% |
| Friday Night | 66°F | Slight Chance Showers And Thunderstorms | 3 mph SSW | 19% |
| Saturday | 86°F | Slight Chance Rain Showers then Mostly Sunny | 5 mph SSW | 19% |
| Saturday Night | 69°F | Mostly Clear | 6 mph S | 14% |
| Sunday | 88°F | Sunny | 6 to 10 mph SSW | 7% |
| Sunday Night | 71°F | Mostly Clear | 9 mph SSW | 10% |
| Monday | 89°F | Mostly Sunny | 10 mph SSW | 11% |
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 Aug 4, 2026.