Duck and Cover

First things first: stay in the shade as much as possible during the sun’s peak hours, between 10:00 am and 4:00 pm. For babies less than 6 months old, avoid all sun exposure.

When outside, cover up with lightweight clothing, a broad-brimmed hat and protective sunglasses that filter ultraviolet (UV) light. You know your clothing screens out harmful UV rays if you can’t see your hand through the fabric. A dry, white T-shirt typically offers a sun protection factor (SPF) of 7; dark clothing with a tight weave offers even more protection.

Study Your Sunscreen

Scrutinize your sunscreen’s active ingredients list. Look for mineral-based sunscreens with zinc oxide and titanium dioxide, classified by the FDA as safe and effective. Also prioritize “broad-spectrum,” which means the sunscreen filters out both UVA and UVB rays. To learn more, check out Sunscreen: How to Help Protect Your Skin from the Sun.

Use Sunscreen Rain or Shine

When considering protection against UV light, be aware of both UVA and UVB rays. Even though UVB causes sunburns, UVA is just as dangerous, as it affects collagen, which gives the skin its strength and helps the body replace dead skin cells. UVA also accelerates sagging and discoloration.

Up to 80% of the sun’s UV rays can pass through clouds, so apply sunscreen daily, even on overcast or rainy days. Regular daily use of SPF 15 (or higher) sunscreen reduces the risk of developing melanoma, the worst kind of skin cancer, by 50%.

“UVA rays also pass through glass,” Dr. Hladik adds. “So if you’re in the car or you sit by a window at work, don’t skip the sunscreen.”

Go for 30

Many doctors, along with the American Academy of Dermatology, recommend water-resistant sunscreens with at least SPF 30.

The SPF number indicates how long you can stay in the sun without burning. For example, SPF 15 means that, theoretically, you could stay out 15 times longer before you get sunburned than if you used no sunscreen at all. In reality, it’s not quite so simple. Multiple factors affect how well you’re protected from the sun, include your genetic makeup, location and time of day.

Apply Enough and Often

Most people don’t use enough sunscreen. You need at least 1 ounce — enough to fill a shot glass — to cover the exposed areas of an adult body.

Sun reflects off sand, water and pavement, so make sure to apply sunscreen to every bare area for complete protection from above or below. Don’t forget your ears, scalp and the back of your neck, and protect your lips with a balm that contains sunscreen.   

Apply sunscreen to dry skin 15 minutes before going outside; it takes that long to start working. Then reapply every two to three hours or after swimming, even if you’re using a product that claims to be waterproof or to offer all-day protection. Every sunscreen washes, rubs and sweats off easily.