I cast on 42 for my yellow hat so I cast on 40 for this one. I found a tutorial online showing you how to join the round so that it's seamless and I'm glad I did because it looks so much better than the join on the yellow one!
I cast on 40 stitches and used a 9mm circular needle and worked in a round. The yarn is by Lion Brand Hometown, Key Largo Tweed Color. I did severals rows of knit one, purl one and then just knit all the way up to the length I thought was good enough for my kids. It was about 6.5 inches (including brim) and the circumference was about 17.5 inches but it's really stretchy. Of course, a pom pom is a must!
I made a few more for the other 2 boys! Hubby forgot to put on his!