Shorts in the winter?!

Christmas is right around the corner. So that means we are almost in the middle of winter. Speaking of winter, I have a question for you: What do you make of Japanese schoolchildren having to wear shorts all year round? Yes, for those of you who do not know, this is true. Japanese elementary schoolchildren wear shorts to school in the winter!!! Are their parent crazy? Are the teachers crazy? That is a formula to get the flu! or pneumonia!!! No wonder so many young kids get the flu and sometimes school is closed. Anyway, read below for the opinions of a few foreign residents in Japan.
http://search.japantimes.co.jp/cgi-bin/fl20090630vf.html

I think it is unbelievable. I have been in Japan for over 10 years now, and I still don't get it. When I see the dry-looking, frozen-looking legs of kids running around in shorts in the winter, I become speechless. WHY?! Can someone please answer this question for me. Personally, I wear many layers of clothes in the winter; at least 3 on top(a tee-shirt, long sleeved shirt, and a sweater), and usually two on the bottom(long johns and jeans). How these kids survive in the winter wearing shorts is beyond me...