Frequently Asked Questions

Sun Exposure reads the Time in Daylight that your Apple Watch records in Apple Health, so it needs a compatible Apple Watch and permission to read that data.

To check, open the Settings app on your iPhone, go to Privacy & Security > Health > Sun Exposure, and turn on every category.

Time in Daylight is recorded by Apple Watch Series 6 and later, Apple Watch SE (2nd generation) and later, and every Apple Watch Ultra, with watchOS 10 or later. The first-generation Apple Watch SE and Series 5 and earlier can't record it.

Open the Health app and check Browse > Other Data > Time in Daylight. If it's empty there too, your watch isn't recording it:

• On your Apple Watch, open Settings > Privacy & Security > Health and make sure Time in Daylight is on.
• On your iPhone, open Settings > Privacy & Security > Location Services > System Services and make sure Motion Calibration & Distance is on.
• Wear your watch outdoors with the screen uncovered. The light sensor is in the display, so a sleeve blocks it. It doesn't have to be sunny; cloudy days count too.

If Health has data but Sun Exposure doesn't, set Minimum Lux to None in Settings > Goals & Alerts.

Your Apple Watch saves Time in Daylight in batches, and Health syncs it to your iPhone in the background, so new time can take a while to appear, especially on your iPhone. Opening Sun Exposure on your watch shows the latest data it has saved, and adding a Sun Exposure widget helps the app refresh more often.

Yes. Start a Sun Session on your iPhone when you head outside, and end it when you come back in. Sessions only count daylight hours, and when you end one it's saved to Apple Health as Time in Daylight, with a vitamin D estimate if you have Sun Exposure Pro.

Start a session with the sun button at the top of the Today tab, from Control Center, or with Siri, then pause or end it from the Lock Screen. You'll need to set your skin type first.

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.

Your daily goal is a range, 20 minutes to 1 hour by default. You reach your goal when your Time in Daylight passes the minimum, and go over it when you pass the maximum. With Sun Exposure Pro you can change both in Settings > Goals & Alerts.

A day counts toward your streak when it ends inside your goal range, so going over your maximum ends your streak. Talk to your doctor about how much sun is right for you.

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.

Minimum Lux leaves out time spent in light dimmer than the level you choose, such as sitting near a window. To count everything Health counts, set Minimum Lux to None in Settings > Goals & Alerts.

Sun Exposure combines the hourly UV Index where you are with the Time in Daylight your watch measured and how bright it was: full sun counts fully, while shade counts less or not at all. It then adjusts for your skin type and how much skin you have exposed, which you can set in Settings > Skin & Health.

It's an estimate of what your skin makes from sunlight, not a measurement of your vitamin D levels, and it doesn't include food or supplements.

Your skin makes little to no vitamin D when the UV Index is below 3, which is common early and late in the day, in winter, and far from the equator. Time in shade or dim light doesn't count either.

Also check that your skin type is set, that your skin coverage isn't Full Coverage, and that Sun Exposure can use your location to get the UV Index. Vitamin D estimates are part of Sun Exposure Pro.

Turn on Auto-Log to Health in Settings > Skin & Health. It needs Sun Exposure Pro and your skin type. Sun Exposure then saves the vitamin D it estimates from your Apple Watch's Time in Daylight to Apple Health throughout the day, under Nutrition > Vitamin D.

Before saving, it checks how much vitamin D Sun Exposure has already saved today on either device and only adds the difference, so your iPhone and Apple Watch don't log the same sun twice. Vitamin D that other apps log, such as supplements, doesn't change what Sun Exposure logs. It uses the day's UV Index, which Sun Exposure gets when you open the app or a widget refreshes.

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.

Sun Exposure uses the Fitzpatrick scale, from Type I (always burns, never tans) to Type VI (never burns, deeply pigmented). 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.

Your skin type affects both Burn Time and vitamin D estimates.

First Light is the time your Apple Watch first measured daylight each day, and how long after sunrise that was. Getting daylight soon after waking helps anchor your circadian rhythm.

If you track your sleep and allow Sleep access, First Light also shows how soon after waking you got outside. You can set a Time to First Light goal in Settings > Goals & Alerts. First Light is part of Sun Exposure Pro.

Time in Daylight tracking, history, streaks, Sun Sessions and goal alerts are free. Pro adds the UV Index and weather forecast, Burn Time and Burn Time Alerts, vitamin D estimates and auto-logging, First Light, sunrise and sunset times, custom goals, reminders, and the Minimum Lux setting.

Open Sun Exposure on your iPhone first; your Apple Watch gets your Pro status from your phone. If it's still locked, go to Settings > Manage Subscription on your iPhone and restore your purchase.

Yes. Every stat has a widget for your Home Screen and Lock Screen and a complication for your watch face. There's also a Control Center control for starting and ending Sun Sessions.

Yes. Ask Siri things like "How much sun have I gotten in Sun Exposure" or "What's the UV index in Sun Exposure". On iPhone, you can also start, pause and end a Sun Session with Siri, and every action is available in the Shortcuts app.

History only goes back to when your Apple Watch started recording Time in Daylight. Health can also share just your recent data with an app; if you chose that for Sun Exposure, earlier days won't appear. You can share all of your data in the Health app.

Your settings, your Sun Sessions (including where they took place), and a summary of your recent sun exposure and last known location are kept in your iCloud account so they stay in sync across your devices. Only devices signed in to your Apple Account can read them, not the developer of Sun Exposure. Apple encrypts this data in transit and on its servers, though unlike your Health data it isn't end-to-end encrypted.

The Time in Daylight and vitamin D records themselves are stored in Apple Health, which end-to-end encrypts them when it syncs with iCloud. To keep Sun Exposure's data out of iCloud, turn off Sun Exposure in the Settings app under your name > iCloud.

Settings sync between your iPhone and Apple Watch automatically. If they don't match, tap Sync Settings near the bottom of Settings on the device that has the settings you want to keep.