UV Index Today

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UV Index Guide

Short answers on UV, sunscreen, and related questions. For news and longer reads, see the Blog.

Sunscreen Essentials

Does Sunscreen Expire?

Yes—usually within three years, and heat-damaged bottles may underperform.

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Does Sunscreen Prevent Tanning?

It slows tanning but won't stop it completely if UVA gets through or you under-apply.

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How Long Does Sunscreen Last?

Reapply every two hours—sooner if you're swimming, sweating, or toweling off.

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Does Sunscreen Cause Cancer?

No—UV causes skin cancer; sunscreen lowers that risk.

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How Does Sunscreen Work?

It reflects UV or absorbs it and turns it into heat—either way, less reaches your cells.

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What Does SPF Stand For in Sunscreen?

Sun Protection Factor—how well a product blocks UVB, not how long you can stay outside.

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Everyday UV Protection

What UV Index Requires Sunscreen?

The WHO recommends sunscreen once the UV index reaches 3.

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Do Sunroofs Have UV Protection in the Genesis GV70?

Factory sunroof glass blocks some UV, but exact specs vary by year and trim.

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Does Glass Block UV Light?

Regular glass blocks most UVB but lets a lot of UVA through.

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Do Car Windows Block UV?

Windshields block most UVA; side windows do not.

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UV & Your Health

What Are Good UV Rays for Tanning?

There aren't any—tanning is your skin's response to UV damage.

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Can UV Light Cause Cancer?

Yes—UV from the sun and tanning beds is a known cause of skin cancer.

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UV Science & Tech

Does UV Light Kill Bed Bugs?

UV-C can kill bed bugs in lab tests, but it won't reach the ones hiding in your mattress.

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Does UV Light Kill Mold?

UV-C kills mold on surfaces it can reach, but it won't fix moisture or mold inside walls.

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What Is UV Light Used For?

UV disinfects water and hospitals, cures inks, and shows up in forensics—beyond sunburn.

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Does UV Light Dry Regular Nail Polish?

No—regular polish dries by evaporation. UV lamps only cure gel polish.

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Does UV Light Kill Bacteria?

Yes—UV-C damages bacteria's DNA, which is why it's used in water treatment and hospitals.

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Do Plants Need UV Light?

Plants need red and blue light to grow; UV is optional, not required.

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UV Index Records

What Is the Highest UV Index Ever Recorded?

The highest commonly cited ground-level reading is about 43, measured at Bolivia's Licancabur volcano.

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What Place Has the Highest UV Index?

The highest routine UV levels are in the high Andes, where altitude and latitude stack up.

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