Wool felt and warm weather? "The Duster" is another beautiful felt hat that spells comfort all the way! Being extremely water repellent and crushable it will soon become your favorite hat. Most people think that a felt hat is a hat for cold weather only. NOPE! sorry, we didn't mean to shout. Natural materials like wool have remarkable thermostatic properties that are capable of retaining needed heat in cold weather and yet will actively release excess heat under warm conditions. For most people, a comfortable range of a wool felt hat is in the area of 40 to 80 degrees Fahrenheit or 4.44 to 26.66 degrees Celsius, a great sun hat.