These five tips from board-certified dermatologists explain which type of sunscreen to choose, how to apply it correctly, and when to reapply.

1. Choose the Right Sunscreen

Choose a sunscreen with an SPF of 30 or higher that is water-resistant and provides broad-spectrum protection against UVA and UVB rays.

A tinted sunscreen containing iron oxide offers additional protection against the development of dark spots. Iron oxide helps protect your skin from the sun’s visible light.

2. Apply Sunscreen Before Going Outdoors

Apply sunscreen approximately 15 minutes before going outside, allowing time for your skin to absorb it and become protected. If you wait until you are already in the sun, your skin remains unprotected during that time and can burn.

3. Use Enough Sunscreen

Most adults need at least 1 ounce of sunscreen—approximately 30 milliliters, or enough to fill a shot glass—to cover all skin not covered by clothing. Depending on your body size, you may need more.

For your face, use at least 1 teaspoon. The AAD describes this as approximately the amount needed to cover the length of your index and middle fingers. Rub the sunscreen thoroughly and evenly into your skin.

4. Cover All Exposed Skin

Apply sunscreen to all skin not covered by clothing. Remember your neck, face, ears, the tops of your feet, and your legs.

For hard-to-reach areas such as your back, ask someone to help or use a spray sunscreen.

If you have thinning hair, apply sunscreen to exposed areas of your scalp or wear a wide-brimmed hat. Protect your lips with a lip balm containing SPF 30 or higher.

5. Reapply Regularly

When outdoors, reapply sunscreen every two hours and immediately after swimming or sweating.

People who get sunburned often have not reapplied sunscreen, have used too little, or have applied a product that has expired.

Sunscreen Is Not Just for Sunny Days

Your skin is exposed to the sun’s harmful UV rays whenever you go outside—even on cloudy days and during winter. Whether you are on vacation or taking a brisk walk in your neighborhood, remember to use sunscreen.