Butterfly flight seasons in Pennsylvania from 117,920 research-grade iNaturalist observations. August has the most activity.
By month
Pennsylvania butterfly calendar (top 40)
Fewer More observations (relative to each row's peak month)
Activity by month (all species)
Most-photographed butterflies in Pennsylvania
Monarch
Eastern Tiger Swallowtail
Huron Skipper
Small White
Silver-spotted Skipper
Spicebush Swallowtail
Black Swallowtail
Great Spangled Fritillary
Zabulon Skipper
Pearl Crescent
Red Admiral
Peck's Skipper
Eastern Tailed-Blue
Eastern Comma
Variegated Fritillary
Red-spotted Admiral
