Look for broad-spectrum sunscreens with at least an SPF 15. Broad-spectrum formulas block both UV-A and UV-B rays and offer the highest level of protection from the sun's ultraviolet rays. UVB radiation are the rays that cause sunburn and contribute to skin cancer, while UVA rays absorb deeply into the skin and cause wrinkles and premature aging. The SPF factor refers only to the sunscreens UVB protection--not its UVA protection.

Choose a waterproof sunscreen if you will be swimming or participating in activities that will cause you to sweat. Although the waterproof formulas will keep your skin protected longer, you will need to reapply it after excessive sweating or a long swim.

Consider your skin type when choosing a sunscreen. Sunscreen formulas are available for both sensitive and oily skin types to help prevent clogged pores and skin reactions in highly sensitive people.