We spent 6 days in Italy, in temperatures which were normally 35-38 degrees. At about 2pm, the sun was directly overhead and it was very hot as we walked (and walked...) around Italy.
One great thing was the supply of fresh, cool water. It was possible to pay 3 Euros for a small bottle of drinking water near some of the monuments, or instead, keep the bottles and refill them at the many fountains. The water was delicious - cool and fresh. Apparently the Romans have been doing this since they used aquaducts - and we are highly appreciative. We would often refill our bottles and have a rinse to cool off - however Cameron's version of this sometimes looked more like a swim!!
We loved Italy. 6 days is nowhere near enough, but it was great for the family to get a 'taste' (and not just for bruschetta!)