Vintage tees & plaid shirts are great on their own and for layering
Overalls and short dresses are comfy, yet look great when layered
In Japan, its the cool period right now, cool enough that its no longer sticky & humid but yet enough to start experimenting abit with warm clothes though its not cold enough to swaddle one's self in coats and furs.
Here's some clothes to have fun with during this period of "perfect" weather...
All images from http://www.shareapic.net/708081-Seventeen---October-2009.html