I usually wear 7 5/8.  The L/XL was slightly big but easily adjusted to perfect fit with adjustable inner band.  It traveled to Rome folded in a suitcase and popped back into shape.  I wore it for 8 days in Rome, folding it up and carrying it in a shoulder bag when I didn't need it without a problem.  I never wore it in heavy rain but light rain didn't bother-I thoroughly Scotch-guarded it before I left.  I found it to be cool and comfortable in mid-70s, sunny weather.  All in all, a good-looking, functional hat that travels well.