Sunscreen should be worn every day, regardless of the weather or season. Sun exposure occurs all day long, through clouds, through regular glass windows of our homes and cars, and in the time spent walking to the grocery store or driving in the car.
Limiting sun exposure, by wearing hats/gloves/sun protective clothing and avoiding exposure between 10am-2pm, is essential. You should wear sunscreen every day on exposed areas (i.e., face, neck, V-neck, chest, hands/forearms, and legs) for both skin cancer protection and defense against photo-aging.
SPF (Sun Protection Factor) is defined as a ratio of time in the sun required to sunburn with sunscreen on to the length of time in the sun required to burn without sunscreen.
Choose a daily sunscreen that is at least SPF30 (if you have dark skin) or SPF40-50 (if you have light skin) and has both UVA and UVB (i.e. broad spectrum) coverage. If you have a personal or family history of skin cancer, or if you are often outdoors, consider using a sunscreen with higher than SPF 50.
There are two basic types of sunscreen:
physically blocks ultraviolet radiation. Active ingredients include zinc oxide or titanium dioxide.
contain special chemicals that absorb ultraviolet radiation such as oxybenzone, avobenzone, ecamsule, padimate O,PABA, octyl methoxycinnamate, octyl salicylate, phenylbenzimidazole sulfonic acid, homosalate, octisalate, octocrylene, octinoxate.
There are now many different types of sunscreen products, and it is recommended that you choose one that matches your daily activities and/or skin-type.
For face: UVA/UVB (broad spectrum) coverage higher than SPF30 is recommended
For lips: lip-balm containing SPF30 is recommended
For body: UVA/UVB (broad spectrum) coverage greater than SPF50 is recommended
What about sun protection for sports and outdoor activities?
For water sports, a wetsuit or UV-proof (SPF50) water jersey is recommended. Other sun-exposed areas require special sunscreens that will stay on in the water or after sweating. They need to be reapplied often, especially after sweating, toweling off or after extended periods of time when skin is immersed in water.