I purchased this hat two years ago and I used it mainly for kayaking.  I loved the hat.  But, this summer, it got so hot that the foam inside melted and shrank and so it's really small now with the excess outer fabric loose and wrinkled.
Granted, Kavu does warn that if you leave the hat on a car or in the sun it will melt.  But, why would one wear it in the shade?  I think they need to update this hat with better materials that comply with global warming!  hehehe