Italy - Climate and when to go to Italy

Climate
Having the Alps as a northern border and the Mediterranean Sea surrounding much of the country has resulted in a fair and temperate climate. There are five main zones: the Alpine zone, the Northern Italian area, the coastal area, the Adriatic coast and the Mediterranean zone.
The Alpine region experiences harsh winters with plenty of rain and snow and very mild summers. However the weather conditions vary greatly according to the altitude.
The Northern Italian area has fairly cold, snowy winters but warm, mild summers. Northern cities such as Torino, Milan and Venice can become very cold, damp and foggy with temperatures falling to 0-7°C in winter. Most of the rainfall occurs in the spring and summer months.
The Adriatic coast also experiences cold winters, but it becomes comfortably warm in the summer. Temperatures in Rome vary between a low of 5-6°C in winter and a summer high of 26-30°C.
The Mediterranean region, which includes all the southern areas of Italy, rain falls more often in winter while the summer months become dry and hot. 
 
When to go
Italy really does have four seasons. Summer is high season and will be most expensive. Also, holidays such as Easter and Christmas often book quickly.
Low season is between the middle of November and the end of February.