Everything You Need to Know About the UV Index

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Wondering what the Ultraviolet (UV) Index means? Or perhaps you’ve heard of the UV Index, but you’re not sure how to use it. Either way, you’re in luck as we’re sharing everything you need to know about the UV Index. Continue below to learn what it is, how it’s determined and why it matters!

What Is the Ultraviolet (UV) Index?

The Ultraviolet Index forecasts the risk of skin damage from exposure to the sun’s ultraviolet radiation. It’s an invaluable resource when planning to spend any time outdoors.

The index ranges from 0-11+, with the higher values indicating an increased level of radiation exposure. These index values are also grouped by threat level, associated with anywhere from “Low” to “Extreme” levels of overexposure danger. For a TL;DR-friendly video, see below:

How Is the UV Index Calculated?

In the United States, the Ultraviolet Index is calculated by the National Weather Service. Their model predicts the ground-level strength of UV radiation while factoring ozone levels, weather conditions and elevation. This helps predict the length and intensity of UV waves, which determines their impact on our skin. If you are like us and enjoy nerding out over weather models, check out this more detailed explanation from the EPA.

How to Check the UV Index

You can get the UV Index from most popular weather providers, such as The Weather Channel and AccuWeather. If your favorite weather source does not share the Ultraviolet Index, you should consider finding a source that does.

You can also use the following widget to lookup your UV Index by zip code. Give it a try now:

Alternatively, if you have an Alexa-enabled device, you can specifically ask for the day’s Ultraviolet Index, in addition to full weather forecasts. This is a great step to take before leaving the house to help you take the necessary precautions to stay sun safe.

Woman at the beach after checking UV Index

How to Use the Ultraviolet Index

Once you know the index level, it’s time to apply this information and plan around it. Your exact course of action depends on the Ultraviolet Index value, so here’s a breakdown:

UV Index = 0-2 (Low)

Yay! You can safely enjoy the outdoors with even minimal UV protection. We still recommend sunscreen, sunglasses and lightweight UPF apparel.

UV Index = 3-5 (Moderate)

In this range, your risk of exposure increases to the point where sun protection is essential, especially during midday. Apply an SPF 30+ sunscreen and wear a hat, sunglasses and UV protective clothing.

UV Index = 6-7 (High)

Once the Ultraviolet Index reaches 6, you’re in the “High” risk levels. Wear a wide-brimmed hat, sunglasses and long-sleeved UPF apparel, in addition to a broad spectrum SPF 30+ sunscreen. If possible, limit your UV exposure during late morning through mid-afternoon.

UV Index = 8-10 (Very High)

Sun protection is now critical for even short periods of sun exposure. Additionally, indirect UV radiation becomes a greater threat, so beware of surfaces that reflect UV radiation, such as water and sand. Generously apply (and re-apply) sunscreen and wear UPF sun protection clothing, a wide-brimmed sun hat and sunglasses. And remember the “shadow rule!” If your shadow is shorter than you, which is typically near midday, you are exposed to even higher UV radiation levels.

UV Index = 11+ (Extreme)

Today’s gonna be a doozy! If possible, plan any outdoor activities for the morning or late afternoon to avoid the especially high levels of UV radiation around midday. Guard your skin with UPF apparel, sunglasses and a sun hat, and don’t even think about going outside without broad spectrum sunscreen.

Water reflecting UV rays

More Adventure. Less Exposure.

The Ultraviolet Index is not meant to scare you into staying indoors, but to help you go outdoors safely. If you make checking the UV Index part of your daily routine, you’ll stay one step ahead of sun damage.

To prepare for even the most extreme levels of UV radiation, protect yourself with UPF clothing from Rayward Apparel. Shop our sun shirts now, featuring UPF t-shirts, long sleeve shirts and lightweight hoodies!

Source: EPA.gov