There are some interesting cat hat knitting pattern available out there. I also made my own pattern to fit my 6 months old Charlotte. I think the hat will fit 3-9 months old. Easy Cat Hat Knitting Pattern by Effi Gratia Size: 3-9 months old Gauge: 2 inches = 9 stitches You’ll need: 1 skein of DK weight yarn (less than 100 m) 4.5 mm or US size 7 DPN or circular needle Tapestry Abbreviations: CO: cast on K: knit P: purl Instructions: CO 60 stitches, join in the round. Knit in 2×2 rib (K2, P2) for 5 rows. Continue the stockinette stitch for 34 stitches or until measures 5