Venice has some of the most extreme overtourism dynamics in Europe. July and August are overwhelmingly crowded, with over 30 million annual visitors concentrated into a very small city. Summer also brings acqua alta (high water flooding) risks in September and October as lagoon tides can flood San Marco Square and surrounding streets. The Venice Carnival in February is one of Europe's most theatrical events, with elaborate masks and costumes filling the campos and calli for two weeks. Book Venice Carnival accommodation at least six months ahead and expect the highest prices of the year outside summer. April and October are the practical choice: manageable crowds, no extreme summer heat, and atmospheric light in the canals. The Venice Film Festival (Mostra) at the Lido in late August and early September is a major cultural event. May and June are warm and increasingly crowded as school holidays begin across Europe. November through January sees the fewest tourists, cooler temperatures (5C to 12C), and frequent morning mist over the canals.