Watch out for the big boys! Um…not those big boys. They're a bit bigger, and louder, than the ones in The Snowy Day.
The big boys Peter encounters are only featured briefly, on a two-page spread near the middle of the book (22-23), but the big boys are an important clue in helping us to understand Peter. The fact that he considers them "big boys" lets us know that Peter is one of the "little boys" who isn't yet ready for things like snowball fights. In their yellow and green outfits, these boys are a stark contrast to Peter, who is enveloped in his voluminous red snowsuit. And while he sits on the ground, seemingly knocked down by one of the snowballs, they continue to play vigorously, which further sets them apart.
Peter notes that he's not old enough to join in their play, at least "not yet" (23). So the Big Boys serve as a contrast to Peter and a reminder that this book is about the innocence and wonderment of youth—not about growing up or engaging in conflict or competition.