Citizens from countries outside the European Union, like the United States, are required to present a passport valid for at least three months beyond the intended stay in Italy. In-case you are a resident of any European Union country, you don’t need to have your passport, but national identity card or NIT is must to travel to almost all parts of Italy.
All Travelers except residents of European Union require to have a valid passport visa for atleast 90 days following the initiation of your departure to Italy.
Weather of Italy varies from top to the bottom of country. Considering the hilly & coastline terrain of Italy you can expect a sudden decline in temperature within minutes. Be prepared, usually during winters weather is at the mark of -5 Degree Celcius to 15 Degree while in summers it can climb upto 30 Degrees in some cities.