This is a variation of the hat I knit again and again. It is done quickly with two strands of Red Heart or I Love This Yarn worsted and size 11 (U.S.) circulars. I switch to my size 10 bamboo double points when I decrease at the crown. The stitch is 2x2 ribbing.
These hats are fast, warm, and can be adjusted in size by going up or down in multiples of 4 stitches cast on.
Variations:
Tweed Hat--Use two different yarns held together
Reflective Hat--Use yarn with a metallic thread