Best Overall: May-September - Warm weather, long days, outdoor activities along the Elbe, park concerts, and festivals.
Spring (April-May): Beautiful with blooming gardens in Großer Garten and Pillnitz. Fewer crowds than summer. Temperatures 10-20°C (50-68°F). Easter markets are charming.
Summer (June-August): Peak season with warm weather (20-25°C/68-77°F), perfect for river activities and outdoor concerts. Expect crowds at major attractions. Long daylight hours ideal for sightseeing. Occasional hot spells above 30°C (86°F).
Autumn (September-October): Excellent choice with mild weather, beautiful fall colors in parks, fewer tourists, and cultural season starting at Semperoper. Temperatures 10-18°C (50-64°F).
Winter (November-March): Cold (0-5°C/32-41°F) but magical, especially during Striezelmarkt Christmas market (late November-December 24), Germany's oldest. Museums less crowded. February is coldest. New Year celebrations are festive.
Avoid if possible: Late January-February (coldest, darkest period) unless you specifically want winter atmosphere.