Acqua alta in Venice: what it is, when it happens and what to do

Acqua alta (literally "high water") frightens many travellers, but the truth is simpler and more reassuring than it seems: it's a natural phenomenon, forecast well in advance and almost always just a few hours long. It isn't a flood or a constant emergency — it's the tide that, on certain autumn and winter days, rises a little more than usual. Here's what it really is, when it happens and how to take it in your stride.

🌊 What acqua alta is

Venice is built on a lagoon, just centimetres above sea level. When high tide combines with the sirocco wind and low pressure, the water rises temporarily and covers the lowest parts of the city. The very lowest is St Mark's Square, which floods first even with modest tides. It usually lasts a few hours around the tidal peak, then the water drains away on its own.

📅 When it happens

Acqua alta is seasonal: it's concentrated between October and January, with the most frequent peaks in November. Even then it's occasional, not daily: many winter days show no trace of it. And when it does come, it's announced well ahead of time.

🛡️ The MOSE: Venice is protected today

Since 2020, Venice has the MOSE, a system of mobile barriers at the lagoon's inlets. When a high tide is forecast, the barriers rise and seal the lagoon off from the sea, preventing flooding. Thanks to the MOSE, the serious episodes that once made the news are now largely avoided — extra peace of mind if you visit in winter.

📱 How to know: the forecasts

The city's Tide Forecast and Warning Centre publishes hour-by-hour forecasts. You can check them on the City of Venice website or through the official City of Venice tides app. If a significant tide is expected, an acoustic signal (a siren followed by tones) warns the city of the expected level. On the main routes, raised walkways are also set up, so you can walk dry-shod.

💡 What to do: practical tips

• Rubber boots: sold everywhere in the city for a few euros, should the peak catch you out and about.
• Follow the walkways and check the app in the morning: plan the low areas (St Mark's) outside the peak hours.
• Waterproof shoes and a little patience: within a few hours the tide drops and the city is back to normal.
• Enjoy the sight: St Mark's Square turning into a mirror of water, reflecting the Basilica, is one of Venice's most striking images.

🏠 And in Cannaregio?

Our neighbourhood isn't among the lowest-lying parts of the city, and Cà Letizia is on the second floor: any acqua alta is no problem for your stay. As with everything else, after booking we give you tailored directions and tips, including how to get around on the (rare) high-tide days.

For the rest of your trip: our vaporetto guide, a weekend in Venice in 2 days and our Venice guide from Cannaregio.

Venice in winter, worry-free

The low season is the most authentic time to experience the city. Send a request for your dates.