Shade shows the live UV index and your estimated burn time on your iPhone and Apple Watch, so you can check UV before and during a run, ride, surf or hike without stopping to dig out your phone. The hourly UV curve helps you pick a time to head out.
Why outdoor sport means more UV
- Hours outside: a long ride or hike adds up to a big dose even at moderate UV.
- Altitude: UV rises as you climb, by around 10 percent per 1,000 metres, according to the WHO.
- Reflection: snow reflects up to 80 percent of UV, and water and sand add more. Surfers get UV from above and from the water.
- Sweat and water: both wash sunscreen off faster than you’d expect.
- Wind and cool air: they make the sun feel weaker than it is.
On your wrist
The free Apple Watch app shows the current UV, your burn time and when UV peaks today. Complications put UV and your burn time on your watch face, so a glance mid-run is enough. With Shade Plus you can also control a sun session from your wrist.
Plan around the curve
The UV forecast shows today’s UV hour by hour. An early run or an evening ride usually means much lower UV than the middle of the day. With Shade Plus, a morning alert tells you on high-UV days how high UV will get and when.
Keep the estimate in perspective
Shade uses the UV forecast for your location. It can’t see that you’re on a glacier, on the water or 2,000 metres up, so on those days your real exposure can be higher than the estimate suggests. Cover up and reapply earlier than the numbers alone would tell you.
About the numbers
UV data comes from Apple Weather. Burn-time estimates follow WHO UV Index guidance and standard Fitzpatrick skin-type values.
Frequently asked questions
Does altitude change the UV index?
Yes. UV gets stronger as you climb, roughly 10 percent for every 1,000 metres according to the WHO. Snow can reflect up to 80 percent of UV, so a mountain day can be far stronger than the valley forecast.
Can I see the UV index on my Apple Watch?
Yes, for free. The Shade watch app shows the current UV, your burn time and today’s peak, and complications put UV on your watch face.
Does sweat affect sunscreen?
Sweat, water and friction from straps or a towel remove sunscreen. WHO advice is to reapply at least every two hours, and more often when you’re sweating or swimming.