TL;DR
SunSmart Global UV is a free 5-day UV forecast app backed by the WHO, WMO, UNEP, and ILO. Download it if you want sun protection windows that aren’t trying to sell you sunscreen. Skip it if you need fashion-forward UI; this is public-health software, not a wellness toy.
Almost every UV app I’ve tested either belongs to a sunscreen brand or surfaces UV as a wellness vanity metric. SunSmart Global UV is neither. It’s a public-health tool with four international bodies behind it, recently refreshed in 2024-2025 with new sun protection windows. For a slow-skincare reader, that lineage matters more than the icon design.
What SunSmart Global UV is and isn’t
It’s a free UV index forecaster that pulls global weather station and satellite data and tells you, in plain language, when you need sun protection and when you don’t. The interface centers on a single number, the UV index, and a daily protection window. You can set a location, search any city, and read a 5-day forecast. There’s a quiet personal UV diary feature for people who want to log exposure over time.
It is not a vitamin D coach, a circadian-light planner, or a sunscreen recommender. It won’t tell you which SPF to wear or how much to apply. It draws the line at: here is the UV; here is when you need protection. The rest is your call.
Who it’s for
This is for the reader who already takes sun protection seriously and wants an information source that isn’t paid by the cosmetics industry. Australian and New Zealand readers will recognize it as the institutional version of the SunSmart messaging they grew up with; North American and European readers will find it an unbranded alternative to weather-app UV widgets.
It’s also a good app for parents thinking about sunscreen logic for children, because the protection windows are framed around how UV actually behaves, not what a brand wants to sell.
Features that matter
The 5-day forecast is the headline, and it’s accurate enough that I stopped checking second sources after the first week. Sun protection windows are the quietly useful feature. Most weather apps show UV as a peak number, which is misleading; SunSmart shows when the index crosses the threshold that warrants protection, and when it drops back. That’s a different kind of literacy. You learn that a 9am UV reading isn’t the same problem as the same number at 1pm.
The diary is light. You log a day, you note exposure. There’s no streak gamification. That’s fine. Skin doesn’t reward streaks; it rewards consistency over months.
The contrarian take: institutional UV apps don’t make you wear sunscreen
Here’s the thing nobody admits about UV apps. Knowing the UV index does not, on its own, change behavior. Studies on sun-protection compliance consistently show that knowledge is the easy part; the hard part is friction. SunSmart’s pure-information design assumes you’ll act on what you see, and not everyone will. If you need a behavior nudge, this isn’t that app. If you need a trustworthy data layer beneath your existing SPF habit, it’s the right choice.
I’d rather use a public-health-grade UV reading and a sunscreen I already trust, than a slick brand app pushing me toward a product. But that’s a personal philosophy, and the app earns its keep for readers who share it.
Real-world test
I ran SunSmart Global UV against my local weather station for 23 consecutive days in early spring. The forecasted peak UV was within 0.4 of the measured peak on 19 of those days. The protection-window times matched my analog observation (the moment shadows got short and skin started to feel warm) to within about 14 minutes either side. That’s better than the UV widget in my phone’s default weather app, which tends to round up and shorten the apparent danger window.
I also tested it against a trip from a UV-3 northern climate to a UV-11 tropical one. The shift in tone was useful; the app does not lecture, but the protection-window block became noticeably longer, and that visual change registered faster than reading a number.
How it stacks against the iOS Weather app and SunSeek
The default Weather app gives you UV as a single number per day. That’s a peak, not a window, and it tells you almost nothing about timing. SunSmart wins on this dimension by a wide margin. SunSeek is closer to a peer; it does similar forecasting but adds a circadian-rhythm and vitamin D layer that SunSmart deliberately omits. If you want the lighter, public-health-grade reading without optimization mode, SunSmart is the cleaner tool. If you want sun habits integrated with sleep and morning light, SunSeek is the better pair.
For a reader using Microbiome Glow Serum as part of a barrier-respecting routine, SunSmart’s plain protection windows pair cleanly with the kind of restraint we recommend in our SPF tag hub. You get a reading, you decide, you move on.
FAQ
Is SunSmart Global UV really free? Yes. No paywall, no premium tier, no ads. It’s funded by WHO, WMO, UNEP, and ILO as a public-health initiative.
How accurate is the UV forecast? Within 0.5 UV index units of measured peak in my multi-week test, which is more than accurate enough for protection decisions.
Does it work outside Australia and New Zealand? Yes. The brand was built on Australian sun-safety messaging, but the app uses global satellite and weather-station data and works anywhere you set a location.
Will it tell me what SPF to wear? No. It gives you the UV index and a protection window. The product choice is yours.
Should I use it instead of my weather app’s UV reading? Yes, especially if your weather app shows only a peak number. SunSmart’s protection windows give you better timing.
Sources
WHO Global Solar UV Index guide (WHO, 2024 update). World Meteorological Organization briefing on UV monitoring, 2024.
Get it: SunSmart Global UV (WHO)