What is the best strap for summer?
A Nato Strap!
A Nato strap is essentially a nylon strap that is threaded through the spring bars of your watch. One advantage of a Nato strap is that if a springbar fails, the watch will not fall to the floor.
The best thing about the strap is that in the summer months, or for countries with humid weather it is a great looking strap and can easily be cleaned.
I just picked up a Olive Green Nato Strap for my Panerai and couldn't be happier!