During the school year I wear a polo, shorts, and tennis shoes when it's warm. If I'm not wearing a polo, it's a tshirt with our school name on it. When it's cold, I'll wear jeans and a quarter-zip type top.
During summer school I wear shorts and a tshirt, but the shirt might not be school related. So I guess more casual, but not that much.
At the PLC Institute last week, some of us realized how laid back our school is compared to many. Some schools were saying their teams have been meeting and planning over the summer, and nobody does that at ours. We just wait until we go back.