It's not for warmer weather (to me) as others have said - In summer it can be too warm.

It IS for days when it's already raining...or you know it's gonna be raining...or your trip weather report is saying lots of rain.  This hat has been with me about 8 yrs I'd guess.  BWCA, out west, down south to the gulf, I've enjoyed it.  It's TOTALLY waterproof. I got the Java/coffee brown version and my wife doesn't even mind it too much, haha.

For some reason, I didn't grab it on my latest trip.  I had a waxed cotton ball cap and my hood on my rain gear...it was ok...but I did find I missed the full coverage that this hat provides.  To stay dry, I had to use the hood too.  I lost a lot of vision and was always fighting the hood on this trip.  Not exactly what you want when you are running a river you thought was calm...but rain blows it out unexpectedly.

I can't say I'll never go without it again - but I can say I'll probably never leave it behind if there's much chance of rain on my trip again.

oh - I will say this - make sure you use this hat with a rainjacket that either has no hood or your hood packs away into the collar like mine.  The OR hat WILL drop all the rain right off the back.  Having a hood "out" would just fill up with water in no time.