Sun ExposureSun Exposure Pro
Burn Time
How long you can stay out at the current UV Index before you burn, based on your skin type and the sun you've already had today.
How Burn Time is calculated
Each skin type can take a certain amount of UV before burning. Sun Exposure works out how much of that you've already used today, from your Apple Watch's Time in Daylight, how bright it was, and the UV Index at the time. Then it shows how long the rest would last at the current UV Index.
Shade counts for less than direct sun, so an afternoon under an umbrella uses less of your budget than the same time in the open.
Burn Time Alert
Turn on Burn Time Alert in Settings › Goals & Alerts and Sun Exposure lets you know when your estimated Burn Time runs out. Ask Siri “How long until I burn in Sun Exposure?” any time.
Skin types
Sun Exposure uses the Fitzpatrick scale. Choose the type that best matches how your skin reacts to the sun without protection. If you've set a skin type in the Health app, Sun Exposure starts with that one.
| Type | How your skin reacts to the sun |
|---|---|
| I | Always burns, never tans |
| II | Usually burns, tans minimally |
| III | Sometimes burns, tans gradually |
| IV | Rarely burns, tans easily |
| V | Very rarely burns, tans very easily |
| VI | Never burns, deeply pigmented |
What it doesn't know
Burn Time doesn't know about sunscreen, hats, or UV reflected off water, sand or snow. Treat it as a rough guide, not a guarantee, and protect your skin regardless.
What you need
- Sun Exposure Pro.
- Your skin type, set in the app or read from Apple Health.
- Location, for the UV Index. Approximate location is enough.
Questions about Burn Time
How is Burn Time calculated?
Each skin type can take a certain amount of UV before burning. Sun Exposure subtracts the UV you've already had today, based on your watch's Time in Daylight, how bright it was, and the UV Index at the time, then shows how long the rest would last at the current UV Index.
It doesn't know about sunscreen, hats, or UV reflected off water, sand or snow, so treat it as a rough guide, not a guarantee.
What alerts can I get?
Sun Exposure can let you know when you reach your goal and when you go over your maximum. With Sun Exposure Pro you can also get a reminder each time you add a set amount of time in the sun, and a Burn Time Alert when your estimated burn time runs out. Set these up in Settings > Goals & Alerts.
Alerts follow your Time in Daylight, so they can arrive a little late while your watch syncs.
Why does Sun Exposure need my location?
Sun Exposure uses your location to look up the UV Index, the weather, and sunrise and sunset times where you are, and so Sun Sessions only count daylight hours. Your approximate location is enough. Weather data comes from Apple Weather.
Start Your Sun-Smart Journey Today
Free on the App Store for iPhone and Apple Watch.
Download on the App StoreiPhone with iOS 18 or later. Automatic tracking needs an Apple Watch with watchOS 10 or later.
Disclaimer: Sun Exposure gives estimates, not medical advice. Consult your doctor to determine the right amount of sun exposure for you. Always use sunscreen, hats, and shade as needed.