June and July — June and July Saturdays, when the included water park is at its busiest.
Quietest months
May, August and September — May weekdays and August weekdays once Indiana schools return.
Local knowledge: The Voyage is the one line worth planning around. Everything else stays short enough that you can ride on impulse.
How this is worked out
Each day starts from how that weekday normally runs at Holiday World, learned from our own recorded wait snapshots as they accumulate, and is raised for public holidays and school-holiday periods. It is a forecast of relative busyness, not a promise: a 3 means a day that usually runs quiet for this park, not a guarantee of short lines. The further out a date sits, the more it leans on the weekday pattern alone.
Want the live picture instead? Holiday World wait times has today's queues, the hour-by-hour curve and what counts as a normal wait here. Planning a specific day? Open the planner and it will build a route around these crowd levels.