A UV Index app built for more than checking a number

The best UV Index app depends on what you actually want it to do. If you want more than a UV number, T&T is a UV Index app built with tanning in mind: it shows the current/live UV Index for your location, includes a 10-day UV forecast, and combines your Fitzpatrick skin type and the SPF you're wearing with current UV to produce a personalized tanning-time estimate that feeds into a session timer. It doesn't claim to be objectively 'the best' UV app for everyone — it's built for people who want UV information they can act on inside a tanning session, not just a headline number.

Yes. T&T shows the current/live UV Index for your location on the main screen. The UV Index is a standardised international measure of sunburn-producing UV intensity, defined and maintained by the World Health Organization together with WMO, UNEP and ICNIRP.

Yes. T&T includes a 10-day UV forecast so you can see how UV is expected to change and plan sessions in advance. A forecast is a prediction, not a measurement — actual UV on the day can differ from the forecast, especially when weather or cloud cover changes.

T&T takes three inputs — your Fitzpatrick skin type, the SPF you're wearing, and the current/live UV Index at your location — and combines them into a personalized tanning-time estimate. That estimate is a planning tool for a session, not a medical prediction, and it doesn't guarantee that you won't burn.

Yes. The SPF you set in T&T is one of the three inputs to the personalized tanning-time estimate, alongside your Fitzpatrick skin type and the current UV Index. SPF is a protection number, not a time multiplier — the U.S. FDA states explicitly that SPF is not directly related to time of solar exposure. T&T uses SPF as context, not as a stand-alone countdown. See the SPF-for-tanning guide for a deeper walkthrough.

Yes. The Fitzpatrick scale (I–VI) groups skin by how it tends to burn and tan under UV, and T&T uses your Fitzpatrick type as one of the three inputs to every personalized tanning-time estimate. Two people under identical UV wearing the same SPF can still get very different estimated session lengths because their skin responds differently. See the Fitzpatrick-skin-types guide for a full explanation of the scale.

T&T includes UV alerts and can help keep UV conditions on your radar rather than requiring you to check the app manually. Separately, T&T includes sunscreen-reapplication reminders in its free tier — a general reminder feature. T&T doesn't claim a specific reminder cadence, doesn't claim to detect swimming or sweating, and doesn't tie its reminder timing to FDA guidance. FDA sunscreen-reapplication guidance is public-health advice on its own terms. Exact alert mechanics may vary between platforms and app versions.

Yes. T&T has Apple Watch and Wear OS functionality so you can see UV at a glance on your wrist and run a session without pulling out your phone. See the Apple Watch UV Index and Wear OS UV Index guides for the wearable-specific details.

Yes. T&T is available on the App Store for iPhone and iPad and on Google Play for Android. The app is free to download.

No. A personalized tanning-time estimate is a planning tool, not a medical prediction, and it isn't a guarantee against sunburn or any other UV injury. Skin response varies between people; applied sunscreen is usually less protective in practice than in lab conditions; UV changes through the day. The World Health Organization treats solar UV as a known skin-cancer risk factor and recommends limiting exposure and using sunscreen, shade and clothing. Speak to a dermatologist if you have skin concerns.