The harsh rays of the sun can wreak havoc on unprotected skin causing it to sag, tan, and wrinkle, and have even more serious effects like skin cancer. While most of us use protection from the sun in the form of SPF lotions, there could arise a need for stronger protection. The primary tool that we can use for protection against harmful UV rays is clothing. What we wear often acts as the first layer of defense against any form of sun damage. And while our normal clothing may offer a slight degree of protection, most flimsy, light-colored, lightweight, and loosely woven summer clothes do nothing much to protect our skin. In fact, there may be a possibility that they do more harm than good. This is where sun-protective clothing comes into the picture. Made of fabrics that are rated for protection from UV rays, these clothes are designed to protect you from harmful radiations that the sun emits. In this article, we give you a brief overview of how these clothes work, what their defining characteristics are, how they are rated, and other important tips that you will need to keep in mind when wearing them. Ultraviolet rays are of two types - UVA and UVB, both of which can wreak havoc on your skin. While UVA rays are much less powerful, these can cause long-term damage in small doses. UVB rays on the other hand, are the more dangerous of the two and are the ones that cause sunburn. While sunscreens with SPF do provide a certain amount of protection, they still allow a lot of harmful UVA radiation to penetrate your skin. Most doctors recommend that if you are constantly exposed to the sun, you use head-to-toe protection. This is where sun-protection clothing comes in. It is specifically designed to shield the skin from the sun by covering a maximum amount of skin and is made from a fabric rated for its level of ultraviolet or UV protection. Laboratory tests have shown that many typical cotton T-shirts and light-weight fabrics allow 50% of harmful UVB rays to pass through to your skin when dry, and 10% to 20% more when wet. Sun-protective clothing keeps out more UV rays than a sunscreen. For example, if a clothing item is rated UPF 50, then the percentage of UV radiations that are blocked are anywhere between 97.5% to 99%. The measurement of UVA protection in clothing offers an improvement over the traditional SPF rating of sunscreens, which blocks only UVB radiation, while UPF blocks both UVA and UVB. SPF or Sun Protection Factor rating is used for skin applications, while UPF or Ultraviolet Protection Factor is the standard technique for measuring the protective value of fabrics. A self-regulated industry in North America, manufacturers and retailers follow either the AATCC (American Association of Textile Chemists and Colorists) method or the ASTM (American Society for Testing and Materials) method of testing. The most common concern that manufacturers like Coolibar, Solumbra, REI, etc., face is an inherent block against wearing anything that covers you up fully in the warm summer months. But most companies ask you to take into account traditional clothing of people who live in deserts. Lightweight, loose-fitting clothes that cover you from head to toe are a given. Taking into account prejudices though, companies use modern technologies to create clothing that is not only highly breathable but also moisture-wicking, quick-drying, and extremely comfortable. While it is not possible to create a wardrobe fully packed with sun-protection clothing, having these clothes in your cupboard to wear during warm and humid temperatures or in situations when there is prolonged exposure to sun's rays may be a good idea, to protect yourself from harmful exposure.