Sunglasses are not only in the summer only need to wear, in fact, must be used throughout the year. Fine to wear, to wear cloudy. Do not think that the cloudy day the sun is not strong, the weather did not heat, on lightly, unconsciously but more harmful exposure to ultraviolet light. Even if we are thin on the cloudy day, still have to refer to the UV Index forecast, prepared to do a good sunscreen.