When is FRA busiest?

Driven by flights departing in about 1 to 2 hours, once passengers move airside.

Quietest times to travel through FRA

Overnight hours are quiet at most airports, so the quietest slot is often outside the times you can realistically fly. Compare the hours you are actually choosing between.

How this is worked out

A queue is not made of the aircraft moving at that moment. It is made of the people travelling on flights a little later, or the people who have just landed.

So each checkpoint reads a different part of the schedule: check-in looks 2 to 3 hours ahead, security 1 to 2 hours ahead, and passport control looks back at the last hour of arrivals. Every flight is weighted by the typical seat count of the aircraft flying it, because a wide-body fills a hall far faster than a regional jet.

The result is a shape, relative to the airport's own busiest hour of the day. It shows when to avoid, not how long any one queue will be on a given day, which also depends on how many lanes are open.