UV Index
Know your UV index
before you step outside.
The UV index tells you how strong the sun's radiation is right now — so you can choose your sunscreen, your clothing, and your timing with intention. Here's how to check it on any device, and what the numbers actually mean.
Get the live UV forecast for your zip code.
The U.S. Environmental Protection Agency publishes a free tool that shows today's hourly UV forecast for any U.S. zip code or city — pulled directly from the National Weather Service.
Check it in under ten seconds.
iPhone
Using the built-in Weather app
- Open the Weather app — it comes pre-installed on every iPhone.
- Make sure your current location is selected (or tap a city you've added).
- Scroll down past the hourly and 10-day forecast.
- You'll see a tile labeled UV Index — tap it for an hourly breakdown of today's UV strength.
Android
Pixel, Samsung, or any Android phone
- Open Google (the search bar widget on your home screen, the Google app, or google.com).
- Search for UV index or UV index near me.
- Google Weather will show today's UV index at the top of the results, with an hourly forecast you can scroll through.
- Optional: tap Weather at the top of the result to open the full Google Weather page.
The Shadow Test.
Stand in the sun and look at your shadow. Compare its length to your height — that's it.
What the numbers mean.
Frequently asked.
Is the UV index higher in summer or winter?
Higher in summer — the sun sits more directly overhead, so UV rays travel through less atmosphere. But winter UV is not zero. Snow reflects up to 80% of UV back at you, and high altitude (skiing, hiking) intensifies exposure. Check the index before any extended time outdoors, regardless of season.
Do I need sunscreen on cloudy days?
Yes. Up to 80% of UV radiation passes through clouds, and thin cloud cover can actually intensify UV through scattering. If the index reads 3 or higher, wear sunscreen — clouds or not.
How often should I reapply sunscreen?
Every two hours during normal sun exposure. Every 80 minutes if you're swimming, sweating heavily, or toweling off — even if the label says "water resistant." A single application in the morning is not enough for an all-day outing.
What's the difference between mineral and chemical sunscreen?
Mineral sunscreens (zinc oxide, titanium dioxide) sit on top of skin and reflect UV away — they work the moment you apply them and are gentle enough for sensitive skin. Chemical sunscreens absorb UV and convert it to heat, which can irritate reactive skin and require a 15-minute wait before sun exposure. Ginger Armor uses zinc oxide exclusively.
Why does the EPA tool only cover the United States?
The EPA forecast pulls from the U.S. National Weather Service, which only covers U.S. territory. Outside the U.S., search "UV index" in Google or check a global service like the World Health Organization's UV index map or your country's meteorological service.
Does a higher SPF number mean I can stay out longer?
Not really. SPF 30 blocks ~97% of UVB; SPF 50 blocks ~98%. The difference is small, and no sunscreen is "all-day." Reapplication every two hours matters far more than chasing higher SPF numbers.