Italy in March

The weather will be more variable, cooler, and most likely rainier than June.

Frank is right on. But when you live in S. Florida when it's always hot, hotter and hotter with humidity, cool weather in a nice change of pace. It did rain a little too much for my liking in Florence.

I was in Rome and Florence in February last year. Florence is mostly indoors - museums, churches, etc. so I didn't mind the grey skies and bits of drizzle. Rome was warm (60's) and sunny. There were noticeably fewer tourists in Florence than when I was there in October a couple of years earlier. It was my first time in Rome and there were lots of tourists - I can't imagine what it must be like in June or July! There is lots to do indoors in Rome also. Chances are you will have at least a few sunny days to do outdoor things in both places.

go to Weather Underground and put in the various locations and dates and you can see history in detail for the last 15 years. An excellent planning tool...

Do you think the smaller crowds are worth the trade-off of the cooler, rainier weather? What are the cities like in the rain? Would site-seeing be miserable? Planned to do lots of walking. We have school age kids so our only options are spring-break or summer. If these where your only two choices, when would you go and why?

Speaking as a fellow Northwesterner, I would strongly encourage you to do June rather than March. Do you really want to exchange rainy weather for more rainy weather? Although June will be more crowded, there's a good reason - the weather's wonderful. And a little skillful planning will help you avoid the worst of the crowds. The tip is in the time of the day that you choose to go to the more popular sites. Happy travels.

I prefer http://www.weather.com/. Under the Weather Apps choice, you can compare Portland's weather to your destination city. A tip I picked up here on this site. Happy travels.