All 3 of our kids and many of their friends wore shorts and flip flops in the middle of winter-especially in HS. We could never understand it, we simply questioned it, but did not say much about it. After all, they could always go to school or stop off at a friend's house and change clothes anyway, right? Too much to worry about and carry around. Now, they bundle up. Here in Wisconsin it can be 50 in the am and below 0 by evening. Many teenagers and young adults brave the cold without the coat if they have a vehicle.
What irks DH and I to no end is adults with children that we see everywhere, that are ignorant to the weather. The adults have hats on, winter coats zipped up, mittens or gloves on, and warm ugg boots. The babies could have a pr of knit booties, their bare skin of their legs sticking out of short pants, an unzipped sweater and no hat on. Toddlers and young kids have thin coats, no hats, no mittens, no boots, and their coats are unzipped or still in the cart when the family is taking the groceries to the car in very cold snowy weather. Yes, it doesn't cause the colds and flus and sick days, but it lowers their resistance. Any wonder why they are miserable and hyper and crabby sometimes. They are cold, their chests hurt, they have sore throats, their noses are running, their ears hurt, they have headaches, their fingers are numb, their skin hurts from being cold, etc. etc. etc.