Definitely bloomers. I know one thing girls usually sacrifice in the warm weather is their bloomers, but a good pair of cotton bloomers is better against your skin than your petticoat. Plus, I like having the extra security that if their is a gust of wind or something, you are not going to see my underwear. I often wear shorts under my regular skirts too. Plus, in the winter, a pair of heavier bloomers will help keep you warm. I have heard of girls wearing flannel or even polar fleece bloomers. I do not have a pair of heavy ones yet, but I plan on making a pair before winter returns.