How to read the UV Index and keep your skin safe

There are two types of people: those who seek a high UV Index to catch a tan, and those who hide from the sun’s strongest rays.

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What You Need To Know

• The UV Index is a scale from 1-11+
• The higher the number, the more quickly you can get a sunburn
• Sunburns can have lifelong impacts

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The UV Index describes how intense the sun’s harmful ultraviolet rays are. The UV Index is a scale from 1-11+. The higher the number, the more at risk you are for sun damage to your skin.

The UV level is dependent on several factors, including time of day, time of year, latitude, altitude, weather conditions and reflection.

The UV Index is usually highest in the middle of the day when the sun is highest in the sky. In the early morning or late afternoon, the sun’s rays pass through the atmosphere at an angle, so the intensity is reduced. 

While the UV Index is higher in summer, there are factors in winter that can make the sun’s rays harmful. Surfaces such as snow, sand, pavement and water reflect a lot of the UV radiation that reaches them. This is why it’s important to wear sunscreen while skiing in the winter, just like you would on a beach day. 

Speaking of the beach, if you’ve ever traveled to the Caribbean, you may have noticed you burn a lot more quickly there. The sun’s rays get stronger the closer you get to the Equator.

Clouds can help reduce some of the UV radiation, but depending on the thickness of the clouds, sunburn is still possible. 

How to stay safe

While there are many benefits to being outdoors, you’ll want to do it safely:

1. Use and reapply sunscreen.
2. Wear a hat and sunglasses.
3. Find shade.
4. Limit time outside when the UV Index is highest, generally 10 a.m. to 4 p.m.

Too much sun exposure can lead to skin cancer, premature aging and cataracts.

The shadow rule

You can look at your shadow to see how much UV exposure you are getting. 

• In the early morning or late afternoon, if your shadow is taller than you, your UV exposure is likely low.
• In the middle of the day, if your shadow is shorter than you, you’re being exposed to high levels of UV radiation.