To size up this pattern: increase the number of stitches cast on by a multiple of 6 (e.g., 66, 72, 78) so that the K3 P3 rib section comes out evenly. Work to a longer length before putting in the eyelet round, at about 1” less than desired total length of hat.

Coral/green/white hat in Plymouth “Wildflower.”

Pink/red/blue/green/white hat in “Reggio” superwash self-striping sock yarn (no need to make color changes!)