Based on 2,780 research-grade iNaturalist observations in Illinois, Question Mark is most often recorded in July; in Illinois it behaves like a summer visitor / breeder. It ranks #15 among butterflies recorded in the state in our data.
Polygonia interrogationis
Question Mark in Illinois by month
Bars show research-grade observations per month. They mix true seasonality with how often people are outdoors, so treat small numbers with caution.
Also seen in Illinois in July
Monarch
Black Swallowtail
Red Admiral
Eastern Tiger Swallowtail
Silver-spotted Skipper
Pearl Crescent
Eastern Tailed-Blue
Common Buckeye
Places to look in Illinois
State ParkCahokia
Botanical GardenMorton Arboretum
National ForestShawnee National Forest
Botanical GardenChicago Botanic Garden
Botanical GardenLadd Arboretum
State ParkStarved Rock State Park
FAQ
When does Question Mark appear in Illinois?
Mainly May–August, with the most records in July.
How common is Question Mark in Illinois?
It ranks #15 by number of iNaturalist observations among butterflies in Illinois (2,780 records in our sample).