ABOVE: Acqua alta in the Piazza San Marco.

In an article at Veniceforvisitors.com, we describe the flooding known as acqua alta, which occurs when certain tidal and meteorological conditions occur simultaneously. Such flooding is most common in October, November, and December, but it can occur later in the winter and into the early spring. 

If you're worried that your Carnival costume might get soaked or your new shoes might be ruined by a flood tide, visit the Comune di Venezia's Venice Tides page, which forecasts tide levels (and acqua alta) in the days immediately ahead.