Does this hat have any adjustment, my head measurement is 24.5 inches so I'm wondering if the XL is going to fit?

Yes this hat is adjustable! If you buy a looser fitting hat, you can use a clip in the back of the hat to tighten the headband.

The hat is not adjustable, and size XL fits up to a 24" melon. It's darn close to 24.5", though not quite there. I know that even 1/2 inch can mean the difference between a comfy fitting hat and a ridiculous looking brain-constrictor. That said, backcountry.com offers a completely unlimited return policy, so you can get your moola back, or switch it for a bigger hat.. no worries.