Since Italy is in the southern part of Europe, it stays a fairly mild temperature throughout the year. Of course, the further north you get closer to the Alps it’ll be colder, but Sicily can be warm-ish even in the middle of winter.
Rome is a perfect stop on a classic Italy itinerary. It’s the capital city and one of the most visited cities in Italy. Rome can be gritty at times, but definitely deserves its place as the first stop on this itinerary.