than it being hot and crowded in major cities in August and overrun in Rome in April.

I've been there in December, October, July, and March - got mostly great weather on all occasions.

But keep in mind that Italy has a fair amount of climate variation - Milan, Verona, Turin and other cities are in shouting distance of the Alps and can get pretty cold. So if you're going in colder months you might want to plan for something more southern.