April to early June and late September to October are the best times to visit, as the temperatures are not as sweltering as they are in the summer. However, April to June are the months when school buses packed with children visit the most important sites. Easter is considered high season.
The real tourist boom picks up in mid-June, when schools are closed. From July to mid-September, the coastal areas are crammed. Unless you plan to spend time at a seaside resort or on an island, avoid August if you can: The heat is unbearable and most establishments in the cities are closed.
From late October to mid-December, things are quieter, there are fewer tourists in the cities; sites and attractions do tend to close earlier. Things pick up again briefly during the Christmas holidays (Dec 20-Jan 7), when many shops and museums have extended hours. Otherwise, between November and February, hotels and restaurants in resort towns are closed, and the temperatures take a plunge, especially in the mountainous areas.
High season on most airline routes to Sicily usually stretches from June to the beginning of September and around holiday periods (Christmas and Easter). Shoulder season is from April to May and from early September to October; low season is from November 1 to December 19 and from mid-January to March.
Sicily enjoys a relatively mild climate; high temperatures begin in May, often lasting until sometime in October. While the summers can be very hot and dry, the spring and winter months often bring on torrential rains. Surprisingly, even Sicily has its cold waves in winter, with temperatures falling below zero, especially inland. As of late, it's not been uncommon to see minimal snowfall in Palermo.
Although humidity is not stifling, save for the big cities, there is one element that can be brutal: the wind. Being surrounded by three seas Sicily is exposed to all of them, from the scorching sirocco from the Sahara or the blustery north winds that cause trees to uproot and do serious damage.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.