Anyhow, I spun a single ply yarn from a combination of colors and types of wool. I then crocheted the warmest hat I've ever worn. It might be too warm!
It must be the icelandic wool. The yarn, even at single ply, was really thick.
Next time, I might try and spin a thinner yarn, even though I love thick, chunky, uneven "art yarns."
But overall, I am pleased with the hat. Now it needs to get cold enough here for me to wear it outside!