July, August and October — July and August, and Frightmares weekends in October.
Quietest months
May, June and September — May and early June weekdays, and September weekdays.
Local knowledge: Pioneer Day week, around 24 July, is Lagoon's single busiest stretch of the year — a Utah-specific spike that most national crowd calendars miss entirely.
How this is worked out
Each day starts from how that weekday normally runs at Lagoon, 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? Lagoon 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.