One of my favourite movies is So I Married an Axe Murderer, so it's gotta be karma that landed me the parent of a child with a gigantic head. It's a virtual planetoid. It has its own weather system. (Keep this in mind as you note that in these photos my ten-month-old is wearing the largest of the hat's three sizes!)
The hat is worked from the top down in extended half double crochet. You'll have a finished project - complete with pom pom, chin closure and edging - in just a couple of hours.
Since the brim isn't especially stretchy, make the size closest to the child's head size, erring on the larger side. If the hat's a bit too big (as in these photos), you can adjust the chin closure to compensate.
13 ehdc and 8 rows = 4" (10 cm).
I'm a writer, editor, speaker, author of crochet books, blogger, crafter and founder of Mighty Ugly.
I learned how to knit, then I started a crochet website in 2004 (CrochetMe.com), then it all cascaded into a life of yarn and thread and wire and fabric!