Bought a size 8 for my 2.5 yr old, who wears a size a 7. They're perfect, kept her comfy & warm in the cold weather. Highly recommend that you get the waterproofing spray too, especially w./ kids. It'll keep them clean & dry from any wet.
Ordered the light brown. They are as pictured online. My daughter is between sizes so I ordered up, but those were big. We will try the smaller size and see how those fit. They're super comfy.