Lollapalooza 2026's third day was disrupted by severe flooding in Chicago's Grant Park, forcing organisers to delay the festival's opening and cancel most performances scheduled during the resulting gap. The disruption affected the schedules of several artists, with K-pop group CORTIS and English rock band Wolf Alice both having their sets shortened after being rescheduled, highlighting the impact severe weather can have on major outdoor music events.

Organisers pushed the Saturday (1 August) opening back from midday to 3pm local time following heavy overnight rain that left Hutchinson Field, home to two of the festival's stages, waterlogged. CORTIS performed a 40-minute set instead of the planned 50 minutes, while Wolf Alice's hour-long slot was cut to around 30 minutes. Saturday's line-up had included headliners Olivia Dean and JENNIE, alongside The Neighbourhood, Geese, Sienna Spiro, Clipse and Ethel Cain, with the festival's fourth and final day on Sunday set to feature Tate McRae and The xx.