Murnau is good year-round but peaks in summer and early autumn. July and August are warm enough for swimming in the Staffelsee and bring the most visitors from Munich. September and October offer cooler weather, fewer crowds, and the best visibility to the Alps — the Föhn wind that sweeps down from the mountains in autumn can make the mountains look impossibly close and sharp.
Spring is particularly good for the Murnauer Moos: May and June see the bog orchids and the wet meadow flowers at their best, and the Alpine peaks still carry snow above treeline. Winter is cold but manageable; the light on the snow-covered landscape has a particular quality that drew the Blaue Reiter painters here in every season.