I loved the Blue Moon for this- nice heft and stitch definition in a light-worsted yarn. Soft and warm. Big skein will give you 2 hats.
The Channel Island cast on gives a stretchy picot edge for the garter border. The garter border flexes because of the lace above it, creating a shape that outlines the face and covers the ears.
For summer- try a cotton or bamboo blend.
I hope you love this hat as much as I do.