Weather

Venice:
Venice draws legions of tourists during the peak travel months of June through September. The ten-day Carnival in February is another time when visitors fill the city, but it is also one of the most magical. The best time to visit is from late October into April. You may encounter fog and rain during the winter months, but mild and sunny days are also common.

Florence:
The best time to visit Florence is in May, early June, late September and October. Days during those months are usually warm, and quite long. Since most Italians leave their cities in the summer, some restaurants might be closed in Florence. 

Rome:
It's warm all over Italy in summer; it can be very hot in Rome. The high temperatures begin in Rome in May, often lasting until sometime in October. In Rome the weather is warm year-round, averaging 50°F (10°C) in winter. For the most part, it's drier in Italy than in North America, so high temperatures don't seem as bad because the humidity is lower. In Rome, temperatures can stay in the 90s for days, but nights are cooler and much more comfortable. The average high temperatures in central Italy and Rome are 82°F (28°C) in June, 87°F (31°C) in July, and 86°F (30°C) in August; the average lows are 63°F (17°C) in June and 67°F (19°C) in July and August.