This costume is adorable and hysterical! We received so many compliments from so many people. My son is currently 15 months and the costume fit him well. He did end up taking the hat off twice but for the most part he wore it for the majority of the time. We had very light clothing on underneath the costume because it is pretty thick and I didn't want him to get overheated. You'll have to use your best judgement depending on the weather in your area. The wrist holes we're a little small as the other comments mentioned but I was able to get his hands through.