Temperatures in Venice are much more moderate than in Florence or Rome. But personal experience tells me that when it's moderately hot in Venice, you swelter. It's the humidity.
Unlike the other cities of Italy's "Big Three," Venice's rainfall is pretty well distributed throughout the year, totalling just over 32 inches on average. You'll find thunderstorms, particularly in Spring and Autumn. The biggest holiday periods in Venice feature its worst weather: Christmas (wet and cold), Carnevale (foggy and cold), and Venice Film Festival time in August (hot and humid).
The historic climate charts below tell the story.
The best times of the year to visit Venice are from May through early June, then September and October.
Venice is one of the best walking cities in the universe. As a sea power, the wealth of ideas it brought back from its excursions, especially to the east, resulted in a city whose art and arcitecture is unique, interesting, and diverse. Wander the city, get away from Piazza San Marco and the tourists and squeeze through the narrow passageways for a day. Then, when you want it all explained to you, take a tour. We prefer the scholarly tours put on by Context Travel, where you can find out about Byzantine or Medieval Venice, or find out how the Plague influenced life in Venice, or simply explore a Venice neighborhood of your choosing. See: Context Travel Venice Tours.
More information on planning your vacation to Venice, Italy.
Venice, Italy Travel Essentials
Venice Bed & Breakfast - VeniceBy.Com
Venice Airport Hotels (Marco Polo Airport VCE)
Veneto Hotels