May to September offers the most pleasant weather with temperatures between 15-25°C (59-77°F). Summer (July-August) is peak tourist season with numerous festivals and outdoor activities, though it attracts larger crowds. Spring (April-May) brings blooming flowers and mild weather. Autumn (September-October) provides beautiful foliage and comfortable sightseeing conditions.
Winter (November-February) brings cold temperatures (0-5°C / 32-41°F) but less crowding and festive holiday markets. The Danube occasionally freezes, creating unique photo opportunities. Easter to early May and September to October offer the best balance of weather and tourism density.