UV Index Explained: What it Means, How to Check It, and How To Protect Your Skin

The UV Index measures how strong the sun’s ultraviolet (UV) radiation is when you’re outdoors. It’s reported on a scale of 1 to 11+, where 1 means minimal exposure, and 11+ means extremely high exposure.

According to the U.S. Environmental Protection Agency (EPA), here’s what the UV Index means in terms of UV radiation exposure:

• Low Exposure: 1 to 2

• Moderate Exposure: 3 to 5

• High Exposure: 6 to 7

• Very High Exposure: 8 to 10

• Extreme Exposure: 11+

Too much UV radiation can be extremely damaging. It can lead to sunburn and even sun poisoning, and it can greatly increase your chances of developing skin cancer later in life.

Here’s how the UV Index matters, how to check it, and how to plan around it.

Why the UV Index matters

People often think they can predict their risk of sunburn and long-term sun damage based on the cloud cover and the temperature. But even on cloudy days, UV radiation can be high because clouds don’t necessarily block out all UV rays. And even on cooler days, the UV index can still be high depending on how sunny it is, the time of year, and your location.

How to check the UV Index

Most online weather reports will give you both the current UV index and the maximum UV index that’s forecasted for that day. (Different sites are set up differently, so you may need to poke around to find what you’re looking for.)

Some sites, like accuweather.com, will also give you the forecasted UV index by the hour. This can be especially helpful in planning your outdoor activities.

Why you should check the UV index before you go outside

To prevent sunburn and skin cancer, you need to make informed choices about when to go outside, what to wear, and whether to apply sunscreen. And it’s not just about what the conditions are like right now. Rather, it’s about what they will be like for the entire time you plan to be outside. And the most accurate predictor of how dangerous the sun’s UV rays will be is not the temperature or the cloud cover, but the UV index.

What to do if the UV Index isn’t low

If the forecasted UV exposure is “very high” or “extreme,” you may choose to shift your outdoor activities to a time of day when UV radiation is less intense. Or you may decide to opt for a shady walk in the woods instead of a walk on the beach or on city streets — or do your daily run on an indoor treadmill rather than outside.

The EPA recommends using a sunscreen with an SPF 15 or higher if the UV Index is 3 or higher. With a UV Index of 8 or higher, the EPA recommends adding extra protection (such as covering your skin with clothing and sunscreen and wearing a wide-brimmed hat and sunglasses) and seeking shade, if possible.

If you have a history of skin cancer, very fair skin, have a young child, are elderly, or know you are more sensitive to UV radiation, you should take extra precautions beyond what the EPA recommends.

This content was first featured on Good Neighbor Pharmacy’s website, our trusted partner in pharmacy care.