I was recently shopping for some fall clothing for my kids (at Target). The Girl needed some new pants and a few long-sleeved shirts that don't scream "this is a hand-me-down from my brother can't you tell!" The Boy needed a new fall jacket, and a few pairs of pants. I had good luck finding the items for The Girl, she is a tall 2 year old with a long torso, so she is generally wearing size 2T (only if it sports an adjustable waistband) for pants and a 3T for shirts.
The Boy is a little trickier to shop for though. He has the same micro waist his sister has so adjustable waistbands are a necessity. He is almost too tall for 4T pants now, but I guess we will just make him wear high-waters this fall. I am at a loss for what size to buy him. I do occasionally see 5T sized clothes, but not always. I've ventured over to the "boys" section and see size 4 and size 5 clothing, but when comparing to the T series clothes they seem much bigger and baggier (which translates to very sloppy looking 4 year old). Does it make sense that a 5T sized shirt would look like it fits The Boy well, but a size 4/5 shirt looks like he is borrowing one of my old shirts for the day? Is this a result of style, do I just have to get used to my cute little boy swimming in his clothing before he can even demand such a thing?
I found this website, which gives a great summary of the size ranges for kids clothing. I think I will take The Boy's measurements to see where he falls.