Can someone recc a yarn for this hat pattern?

My brother would like me to make him a hat for the cooler months. We live in NY so maybe something merino/cashmere wool would be great.

maybe a nice blend sock yarn? my mom just made similar hats for a soldier’s charity with a merino sock yarn and small needles and they are just so soft. with the merino they will be breathable but warm. she said it took forever with sock yarn and tiny needles but the result was worth it.

I’ll bet this would be a great use for Panda Wool or Panda Silk. The Panda wool is wool/bamboo/nylon and the silk is wool/bamboo/silk. I’m sure it will be lovely!