It doesn’t matter what the weather is, what month or holiday it is, my kids love to wear costumes or just dress up in mismatched clothes all of the time.
I have taken trips to the grocery store with a 5-year-old Superman in the middle of summer when it’s 90 degrees out, and I’ve taken twins to the park, one dressed as a knight and the other as a dragon, both equipped with foam swords to “battle” each other. Some might say that it’s not a good thing to let kids do those sorts of things, but I allow it to an extent–they just love to express themselves.
Freedom of expression, especially when it comes to younger children under age 7, should be allowed at home anytime and occasionally when running errands or playing at the park. My son has always dressed up. First he was into any kind of costume, and now he likes to wear his “fancy clothes” as he calls them, which usually consists of some sort of button up shirt, a belt, tie a hat of whatever he is in the mood for. I let him choose.
I know when I was a child pretty much anything my parents wouldn’t allow me to wear, I wanted to wear, and I would either hide the desired outfit under my clothes or borrow my friends clothes instead.
So why not let kids express themselves when they are younger rather than have them rebel when they are a little older– often in ways that we may not like. It’s just a phase, and it will pass. To this day, I miss taking Superman to the grocery store with me.