Cycling hats and caps
Wearing a cycling cap under your helmet in the summer ensures that your sweat is absorbed, that your head and eyes are protected from the sun and it prevents you from insect bites on your head.
In winter you can also wear a cycling cap under your helmet. A cycling cap also absorbs your sweat in winter but mainly protects you against the cold. It prevents your from heat loss along your head so that you can better maintain your body temperature while cycling. A cycling cap also keeps the low sun out of your eyes and catches the first raindrops that fall between the slots of your helmet.
In winter you can opt for a thermal cycling hat instead of a cycling cap for more warmth on very cold days.