Butterfly flight seasons in Illinois from 127,185 research-grade iNaturalist observations. July has the most activity.
By month
Illinois butterfly calendar (top 40)
Fewer More observations (relative to each row's peak month)
Activity by month (all species)
Most-photographed butterflies in Illinois
Monarch
Black Swallowtail
Red Admiral
Eastern Tiger Swallowtail
Pearl Crescent
Silver-spotted Skipper
Common Buckeye
Small White
Painted Lady
Eastern Tailed-Blue
Fiery Skipper
Orange Sulphur
Peck's Skipper
Hackberry Emperor
Question Mark
Zabulon Skipper
