Spring (April-May) brings pleasant weather, blooming gardens at Palmengarten, and outdoor café season. May to September offers warm, dry conditions perfect for riverfront exploration. Autumn (September-October) provides comfortable temperatures, colorful foliage in parks, and wine harvest activities in nearby Rhine Valley. Winter (December) features Frankfurt's extensive Christmas markets with holiday atmosphere. Summer (June-August) brings crowds and occasional heat; many locals prefer quieter shoulder seasons.