Best time to visit Sullivan, IL
A month-by-month travel weather guide based on NOAA 30-year climate normals.
The most comfortable travel window in Sullivan runs from April through October — 7 months of pleasant temperatures and modest rainfall.
Winter weather. Plan around weather; good for snow sports if applicable.
Daylight ≈ 9h 30m
Winter weather. Plan around weather; good for snow sports if applicable.
Daylight ≈ 10h 30m
Mild but on the chilly side. Pack a jacket; great for hiking and city walks.
Daylight ≈ 11h 44m
Comfortable for most activities. Bring layers; nights can be cool.
Daylight ≈ 13h 3m
Comfortable for most activities. Bring layers; nights can be cool.
Daylight ≈ 14h 11m
Comfortable for most activities. Bring layers; nights can be cool.
Daylight ≈ 14h 45m
Comfortable for most activities. Bring layers; nights can be cool.
Daylight ≈ 14h 32m
Comfortable for most activities. Bring layers; nights can be cool.
Daylight ≈ 13h 34m
Comfortable for most activities. Bring layers; nights can be cool.
Daylight ≈ 12h 15m
Comfortable for most activities. Bring layers; nights can be cool.
Daylight ≈ 10h 56m
Mild but on the chilly side. Pack a jacket; great for hiking and city walks.
Daylight ≈ 9h 46m
Winter weather. Plan around weather; good for snow sports if applicable.
Daylight ≈ 9h 13m
Looking for similar climates? See Sullivan's climate twins. Or jump straight to the full climate profile.