Early March or April??
Want to miss crowds.

April - the weather will be better.

IMHO the crowds are not really an issue until mid to late June.

While you are alive.

<IMHO the crowds are not really an issue until mid to late June>

Unless it's Easter week!!!

Without a doubt April!!

End of September, beginning of October. Great weather, no crowds, and wine festivals galore! What more can you ask for?

We like September and early October as well. Weather has been perfect for us the two trips we have made to northern Italy this time of year. (As a matter of fact we found September wonderful for Germany and Austria as well.) Shirley

We were in Italy early May this year and it was perfect. The azaleas on the Spanish Steps were in full bloom, the weather was beautiful in Rome, Florence, Venice, Santa Margherita Ligure, and Cinque Terre. We had days in the 70s, with sunny skies. The crowds weren't too heavy yet, either. So I'd suggest late April.

Florence in late May was crowded but the weather was great.

Rome in late November was cold but it was still crowded. Several times, buses and subway trains were full.

So you might as well go when the weather is decent.

Of course, in colder times, accommodations and air fare are cheaper...

Happy to go anytime but I'd prefer April into May. Just go after Easter and enjoy.