The current rule
Italy moves to ora legale — legal time — at 2:00 a.m. local on the last Sunday in March, and returns to ora solare at 3:00 a.m. local on the last Sunday in October. Winter is UTC+01:00, summer UTC+02:00, matching the rest of Central European Time.
A stop-start history
Italy first adopted daylight saving in 1916, abandoned it in 1920, reintroduced it during the 1940s, dropped it again after the war, and finally settled into continuous observance from 1966 during the oil-price pressures of the era. That pattern of adoption during crisis and abandonment in calm is typical: daylight saving has almost always been introduced as an energy measure and retained out of habit.
The energy argument today
Terna, Italy's grid operator, publishes an annual estimate of the electricity saved by ora legale, typically several hundred gigawatt-hours. Independent research elsewhere has found the effect to be small or even negative in modern economies, where air-conditioning load in lighter evenings can outweigh the lighting saved. Italy remains one of the more vocal supporters of keeping the change.