Pitlochry is at its busiest from May through September, when the Festival Theatre is running and the days are long enough to make the most of the surrounding countryside.
May to October is the theatrical season, and the combination of theatre and Highland scenery draws substantial crowds, particularly in July and August. The Pass of Killiecrankie in summer is lush and green; in autumn the gorge turns spectacular gold and orange.
Autumn (September–November) is arguably the best time: the salmon run is at its peak (and with it the fish ladder is at its most impressive), the autumn colour in the wooded valleys of Perthshire is outstanding, and the tourist crowds thin out noticeably after the school holidays end.
Winter is quiet and cold. Most attractions are open but on reduced hours. The hills can carry snow from November through March, which makes walking more demanding but the landscape more dramatic. The town is peaceful without the summer crowds.
Spring (March–May) is good for birdwatching — migrant warblers and flycatchers return to the Killiecrankie woods in April and May, and the hills are still largely uncrowded.