UV Index 3 or Higher? Protect Your Skin, Use SPF 15 or More
The U.S. Centers for Disease Control and Prevention (CDC) says that if the UV index is 3 or higher in your area, protect your skin from the sun in several ways: stay in the shade, wear clothing that covers your arms and legs, wear a hat with a wide brim, wear wrap-around sunglasses that block both UVA and UVB rays, and use a broad-spectrum sunscreen with a sun protection factor (SPF) of 15 or higher. CDC also says it's important to protect your skin all year, not just in summer; UV rays can reach you on cloudy and cool days, and they reflect off water, cement, sand and snow.
CDC says most skin cancers are caused by too much exposure to ultraviolet (UV) rays; in the continental United States, UV rays are strongest from 10 a.m. to 4 p.m. daylight saving time (9 a.m. to 3 p.m. standard time). This article follows CDC's skin cancer prevention and sun safety pages: how to protect yourself, how to use sunscreen, and why to avoid tanning beds. Everyone's health is different; if you have questions, ask your health care provider.
How to protect yourself when the UV index is 3 or higher
CDC explains (CDC, Reducing Risk for Skin Cancer, CDC, Sun Safety Facts):
- Shade: Stay in the shade; CDC says your best bet is to use sunscreen and wear protective clothing even when you're in the shade.
- Clothing: When possible, wear long sleeves and long pants or skirts; if that isn't practical, try to wear a T-shirt or a beach cover-up; tightly woven fabric protects best, a wet T-shirt protects less than a dry one, and darker colors may protect more than lighter ones.
- Hat: Wear a hat with a brim all the way around that shades your face, ears and the back of your neck; tightly woven fabric such as canvas works best, and avoid straw hats with holes that let sunlight through; with a baseball cap, cover your ears and neck with clothing, use sunscreen, or stay in the shade.
- Sunglasses: Sunglasses that block both UVA and UVB rays offer the best protection, and most sunglasses sold in the United States, regardless of cost, meet this standard; wrap-around sunglasses work best because they block UV rays from the side.
- When clothing and hats aren't practical: If protective clothing and a wide-brimmed hat are not practical, apply plenty of sunscreen to all exposed skin, including the ears and the back of the neck.
How to use sunscreen
CDC explains (CDC, Sun Safety Facts):
- Before you go out: Put on broad-spectrum sunscreen that filters both UVA and UVB rays with SPF 15 or higher before going outside; put a thick layer on all exposed skin and get help with hard-to-reach places like your back.
- SPF: The number rates how well sunscreen filters UV rays, and a higher number means more protection; CDC says to use a broad-spectrum sunscreen with SPF 15 or higher.
- Reapply: Sunscreen wears off; put it on again if you stay in the sun for more than 2 hours and after swimming, sweating or toweling off.
- Expiration date: Check the expiration date; sunscreen without one has a shelf life of no more than 3 years, and less if it has been exposed to high temperatures.
- With clothing and hats: Sunscreen works best combined with protective clothing and hats.
- Babies 6 months or younger: Sunscreen is not recommended; the U.S. Food and Drug Administration (FDA) recommends keeping infants out of the sun during midday and using protective clothing if they have to be in the sun.
If you also use insect repellent, apply sunscreen first and repellent second; see Use EPA-Registered Repellent, No OLE or PMD for Kids Under 3; for preventing heat illness in very hot weather, see Heat Stroke, Call 911, Heat Exhaustion, Cool Off, Drink.
Avoid tanning beds
- High UV levels: Using a tanning bed or booth to darken the skin exposes you to high levels of UV rays, and over time too much UV exposure can cause skin cancer and cancer of the eye.
- No protection from sunburn: Indoor tanning does not protect against sunburn; a "base tan" is actually a sign of skin damage.
- A tan is not healthy: Any change in skin color after UV exposure, whether a tan or a burn, is a sign of injury, not health.
What this article did not check
- Skin cancer symptoms and screening: CDC has separate pages; this article did not check them.
- Employer responsibilities: The sun safety page has separate tips and legal notes for employers; this article does not cover them.
- Sunscreen brands: This article does not recommend products.
FAQ
Do I need sun protection on cloudy days?
Yes. CDC says UV rays can reach you on cloudy and cool days, and sun protection matters all year.
How often should I reapply sunscreen?
CDC says to reapply if you stay in the sun for more than 2 hours and after swimming, sweating or toweling off.
Can babies use sunscreen?
CDC says sunscreen is not recommended for babies 6 months or younger; FDA recommends keeping infants out of the midday sun and using protective clothing if they have to be in the sun.
Is a tan healthier?
No. CDC says any change in skin color after UV exposure, whether a tan or a burn, is a sign of injury, not health.
Sources and date checked
All checked on 2026-11-02.
- CDC, Reducing Risk for Skin Cancer (page dated 2026-06-17):https://www.cdc.gov/skin-cancer/prevention/index.html
- CDC, Sun Safety Facts (page dated 2026-06-17):https://www.cdc.gov/skin-cancer/sun-safety/index.html