Is it appropriate for junior high school girls to wear these thin sandals at school in summer?

Of course, you should wear sandals in summer, but you'd better not wear these shoes when you go to physical education class or run for exercise, which will easily hurt your feet. If you want to wear sandals when you go to physical education class or run, you can bring a pair of sports shoes to school and change them when you want to exercise. I think these sandals are better to wear barefoot. They are not only beautiful, but also very comfortable. Of course, you can wear stockings if you want.