UV Right Now — Your Live UV Index
The dial above shows the ultraviolet radiation reaching the ground at your location right now. The moment the page locates you — or you search a city — it reads the current UV index from live solar data and swings the needle to the matching band on the colour-coded scale. As the index climbs, the sun at the centre brightens and its rays reach further, a deliberate visual echo of what is happening in the sky: more ultraviolet energy arriving, and a greater need to protect your skin and eyes. Below the dial you will find the current index, its safety category, today's forecast peak, an approximate burn time and clear guidance on whether protection is needed.
Unlike temperature, UV is invisible and gives no warning through how it feels — you can burn badly on a cool, breezy day. That is exactly why a UV meter is useful: it makes a hidden hazard visible.
What the UV Index Measures
The UV index is an international standard, developed by the World Health Organization and meteorological agencies, that expresses the intensity of sunburn-causing ultraviolet radiation on a simple open-ended scale starting at zero. It is not a measure of heat or brightness; it is a measure of the biologically effective ultraviolet energy arriving at the surface, weighted toward the wavelengths most damaging to human skin. A reading of 0–2 is low, 3–5 moderate, 6–7 high, 8–10 very high, and 11 or above extreme. Each step of about 2 on the scale roughly doubles the rate at which unprotected skin is affected.
Reading the Colour Bands
The dial's colours are the globally recognised UV index bands, and they carry the same meaning on every official forecast in the world. Green (0–2, Low) means you can safely be outside. Yellow (3–5, Moderate) is the point at which protection becomes worthwhile. Orange (6–7, High) means unprotected skin burns quickly and shade and sunscreen are advised. Red (8–10, Very High) calls for serious care and avoiding the midday sun. Violet (11+, Extreme) means skin can burn in minutes and every precaution is warranted. Because the colours are standardised, learning to read this dial teaches you to read UV forecasts anywhere.
What Drives the UV Index Up
Several factors combine to set the day's UV level. The sun's angle is the biggest: UV peaks when the sun is highest, so it is strongest around solar noon, in summer, and closer to the equator. Altitude matters because there is less atmosphere to absorb UV — it rises by roughly 10–12% for every kilometre of elevation, which is why mountaineers and skiers burn so easily. Cloud cover reduces UV, but far less than people expect: thin or broken cloud lets most of it through. And reflection from snow, water, sand and concrete adds to the UV hitting you from below, sometimes dramatically — fresh snow can nearly double your exposure.
Peak Hours and Timing
Across a typical day the UV index follows a bell-shaped curve, near zero at dawn and dusk and peaking around midday. As a rule of thumb, the hours between about 10am and 4pm carry the great majority of the day's UV, and this is the window when sun protection matters most. The meter shows today's forecast peak alongside the live value so you can see whether UV is still climbing toward its high or easing off for the day. The classic "shadow rule" is a handy field check: when your shadow is shorter than you are tall, the sun is high and UV is strong.
UV and Sun Safety
Protection guidance is tied directly to the index. From moderate (3) upward, the advice is to seek shade during peak hours, wear a wide-brimmed hat and UV-blocking sunglasses, cover up with clothing, and apply a broad-spectrum sunscreen of SPF 30 or higher, reapplied regularly. At very high and extreme levels the emphasis shifts to avoiding direct sun in the middle of the day altogether. The burn-time figure on this meter gives a rough sense of urgency, but it is only a guide: fair, sun-sensitive skin burns far faster than the estimate, and no single number replaces common sense and shade.
UV Index vs Temperature — A Common Confusion
One of the most useful things a UV meter teaches is that UV and temperature are not the same thing. A crisp, clear spring day at altitude can deliver a high UV index while feeling cold, and people are caught out because they judge sun risk by warmth. Conversely, a hot, hazy, humid afternoon may carry a lower index than a cooler but clearer one. The sun's ultraviolet output depends on its angle and the clarity of the air, not on how hot the ground feels — which is why checking the index, rather than the thermometer, is the reliable way to plan protection.
Who Should Watch the UV Index
Everyone benefits from knowing the UV index, but some especially so: parents of young children, whose skin is more vulnerable; people with fair skin, freckles or a history of sunburn; outdoor workers and athletes; skiers and mountaineers exposed to altitude and snow-glare; and anyone taking medication or with a condition that increases photosensitivity. Gardeners, beachgoers and cyclists all accumulate significant sun exposure without noticing. For all of them, a glance at the live index turns an invisible, cumulative risk into a simple, actionable number.
UV Terms Around the World
The concept travels under different names: indice UV in French and Italian, índice UV or índice ultravioleta in Spanish and Portuguese, UV-Index in German. Ultraviolet radiation is rayonnement ultraviolet, radiación ultravioleta or ultraviolette Strahlung depending on where you are. Wherever you travel, the numbered scale and its colours mean the same thing — which is precisely why the WHO created a single global standard.
A Note on How UV Is Forecast
Modern UV index forecasts combine the predicted position of the sun, the expected state of the ozone layer (which absorbs much of the sun's most dangerous UV before it reaches us), forecast cloud cover, altitude and surface reflectivity. The result is the clear-sky-adjusted figure you see on this meter. Because the ozone layer, cloud and the sun's angle all change through the day and the seasons, the index is genuinely dynamic — and reading it live, rather than assuming, is the best way to stay ahead of the sun.