April in Italy.
have been in early march to rome and the weather was in the low 20,s with a little rain but mainly sunny.
Have been in late may [last year] and again low 20,s but loads of rain !
So really the is no set pattern but i'd expect more drier days than wet as the norm.
Be carefull the laws about using the right tyres or carrying chain in Italy may apply,because in the north of Italy many passes are closed sometimes as late as june!
best to check out the rules on this one.