Jerrold's Travel Guides, LLC
Best time to visit Italy
My preferred time to travel in Europe is what those in the travel business referred to as the “Shoulder Season”. Shoulder Season occurs twice a year, roughly that time between Easter to late June, and late Sep to mid November. During shoulder season airplane tickets are lower, tourist crowds are fewer and you are likely to avoid the high heat of summer. On the negative side, traveling during Shoulder Season means a little less day light time and the possibility that some sites may start restricting their operating hours due to dwindling tourist crowds.
If your Italy plans include Venice you might also want to consider high water (tide) periods for the city which run between September to April. High water "acqua alta" in Venice is, most likely, to be worst in November, followed by December, with October taking third place.
Shoulder season is not the best time to plan an Italian beach vacation. If your travel plans call for a beach Holiday you will want to pick a summer month. Just keep in mind, August and the first weeks of September are the time many Europeans head off for their beach holidays; it would be wise to book well in advance if an August trip is in the plans. Also, during the summer months, make certain you book in to a hotel that has air condition.
Winter Travel - I have not been to Italy during the winter. I have been to, colder, , Germany during December and found it to be a lot of fun. The advantage of going to italy during the winter is low airfare cost, possibility of a discounted hotel and, if you go in December, the chance to experience italy's Christmas season. On the negative side going to Italy during the winter means, limited day light hours, dressing for the cold, some attractions away from the major cities might be closed, many (if not most) attractions will restrict their visiting hours. Rome is noted as a year long travel destination, you may not find costs significantly lower in the winter season.
In the end, working around the school and work schedules of your family, you might not be able to choose the season you will visit Italy. The good news is, no matter the season, Italy will surely provide you with some unforgettable travel experiences.