Ordered this costume for my 16 month old daughter for Halloween. The fit on the body was generous but appropriate given that she needed to wear a layer of clothes underneath. The fit of the headpiece was a bit too large for her- it kept dropping over her eyes. As she is the size of an average 2-2.5 year old, I felt that the headpiece was a bit out of proportion. A longer hook and loop strip or a short ribbon tie would improve fit on this part of the costume.
She loved wearing the body and shoe covers, though she pulled the headpiece off repeatedly. She seemed comfortable  as well- not too cold or hot. The costume is too thick to wear in a carseat, but I think a child could wear it in a stroller.

Overall, this costume was a great deal and I was satisfied with my purchase.