Needles:
One 16in/40.5cm circular knitting needle US 10 (6mm) or size to obtain gauge.
One 16in/40.5cm circular knitting needle US 11 (8mm) or size to obtain gauge.
US 11 (8mm) set of 5 double-pointed needles or size needed to obtain gauge.

(Brim is worked in US 10/6mm circular needles, Body is worked in US 11/8mm.)

Hat is worked in rounds from bottom edge to crown. Switch from circular needles to double-pointed needles when necessary during crown shaping.