I started checking long range weather forecasts on the Accuweather site last month. Their "extended" forecasts covers 45 days. At that point, I didn't expect accuracy--only a good estimation of rainy days versus sunny ones--along with getting a general feel for temperature ranges.
This last week I'm getting more realistic forecasts, especially for the first few days after arriving. So far, we are sunny for landing in Rome and sunny for Tuscany, the first leg of our trip. I've also checked the water temperature on the Amalfi Coast and on the Puglian coast... both are pretty warm for this time of year--around 76 degrees Fahrenheit. Great for taking a dip or wading in a tide pool. Certainly good enough for tooling around in a boat for a while. Oh, and the hot air balloon trip we planned for Tuscany looks good so far... sunny. Can't wait.