Over the weekend I snapped some photos of my wurm hat. I have worn it twice and it is very very warm! I think because it's slouchy? I really love it and I recommend the pattern. It's fun, easy and goes wonderfully with TV knitting.
The yarn is by Cosymakes. It is a DK weight wool that's soft and a joy to knit with! I'm thrilled to report I also have plenty of left over yarn to knit up a pair of matching fingerless mitts.
I think next time around when I make this hat again, and I will, I think a wool blend would be fun. Maybe with some alpaca or bamboo or silk, something to give it a bit of drape so it slouches even more.