3 month 6 months 9 months 12 months 24 months 
Height 19" - 23" 23" - 25" 25" - 27" 27" - 29" 31" - 33"
Weight 7 - 12 lbs. 12 - 17 lbs. 17 - 20 lbs. 20 - 22 lbs. 27 - 30 lbs.
Chest 16.5" 17.5" 18.125" 18.5" 20"
Waist 17" 17.75" 18.5" 19" 20.25"
Hip 17" 18" 19" 19.25" 20.25"
Inseam 6.75" 8" 8.625" 9.25" 11.75"
Head 16.5" 17.5" 18" 18.5" 19.5"

Graphic describing size chart references