FAQs What is the coolest fabric to wear in a heatwave? Muslin, cheesecloth, and double gauze are among the coolest fabrics you can wear in a heatwave. All are woven from 100% cotton with a loose, open structure that allows air to circulate freely and moisture to evaporate quickly, keeping body temperature lower than synthetic or tightly woven fabrics. Is muslin good for hot weather? Yes — muslin is one of the best fabrics for hot weather.