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UV index today
The live UV index for your exact location, hour by hour through the day — with what each level actually asks of your skin: which SPF, how much, and when shade beats sunscreen.
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The science
What the UV index actually measures
01
The UV index is a WHO-standardized 0–11+ scale for the intensity of skin-damaging ultraviolet radiation reaching the ground. It combines UVB (the burning wavelengths, strongest at midday) and UVA (the aging wavelengths, present most of the daylight hours) weighted by how much each damages skin. A UV index of 6 delivers roughly twice the damaging radiation of 3 — the scale is linear in dose, so the number maps directly onto how fast unprotected skin burns.
02
Location, time, season, altitude, and cloud cover all move it, which is why a live local reading beats any rule of thumb. Two of its behaviors surprise people: clouds cut brightness far more than they cut UV (an overcast day can still read High), and reflection from water, sand, or snow adds a second dose from below. Temperature is irrelevant — a cold, clear spring day can out-UV a hot, hazy summer one.
03
This tool pulls hourly forecasts from Open-Meteo, the same numerical weather models national services use. The practical readout: below 3, most skin needs no extra protection; 3–7, SPF 30+ and midday awareness; 8+, sunscreen alone is not enough — shade and clothing do the heavy lifting. Sun exposure drives most visible skin aging, which is why the SkinPal app tracks your skin alongside your habits — the UV you take today shows up in texture and spots years later.
Reading the scale: what each band asks of you
Low (0–2): no special protection for most people, though dermatologists still recommend daily SPF on the face because UVA — the wavelength band behind most photoaging — penetrates glass and clouds at every index level. Moderate (3–5): SPF 30+ on exposed skin, sunglasses, and some midday awareness; this is the band most temperate climates live in for half the year. High (6–7): reapply every two hours outdoors, favor shade between 10am and 4pm, and add a hat if you are out for more than an hour.
Very high (8–10): unprotected fair skin burns in around 15 minutes; sunscreen becomes the backup rather than the plan, with shade and clothing doing the primary work. Extreme (11+): typical of high-altitude, equatorial, or ozone-thin conditions — minimize midday exposure entirely. The bands are not linear in feel: UV 8 is not "a bit worse" than 4, it is double the damaging dose.
The two-finger rule, and why applied SPF is lower than the label
SPF ratings are tested at 2mg of sunscreen per square centimeter of skin — far more than most people apply. Real-world studies consistently find people use a quarter to a half of that, and protection falls roughly exponentially with dose: a half-dose of SPF 50 delivers something closer to SPF 7–15 in practice. This is the single biggest gap between what people think their sunscreen does and what it does.
The fix is a dosing habit, not a better product. For face and neck, use two full finger-lengths of sunscreen (about ¼ teaspoon) — the two-finger rule. For the body, a shot-glass-sized amount covers an adult in swimwear. Reapplication every two hours of sun exposure matters because the film degrades with UV itself, sweat, and touch — our SPF reapply calculator turns that into a schedule for your actual day.
UV and visible skin aging
The classic twin studies and the landmark 2013 randomized trial in Annals of Internal Medicine point the same direction: daily sunscreen use measurably slows visible skin aging — wrinkling, texture change, and pigment spots — compared to discretionary use, even in adults who start late. Photoaging is cumulative and dose-dependent, which makes today’s UV index the single most predictive daily number for how your skin will look in a decade.
That is also why UV awareness pairs naturally with tracking. A sunscreen habit takes weeks to build and years to pay off visibly; seeing your skin scores hold steady while the habit runs is the feedback loop that keeps it alive. The SkinPal app scores texture, spots, and evenness from a scan so the payoff stops being invisible.
FAQ
Common questions
What UV index is safe?+
Below 3 is low risk for most skin — no special protection needed, though daily SPF remains a good anti-aging habit since UVA penetrates at lower levels. From 3 upward, sunscreen on exposed skin; from 8 upward, add shade and clothing.
What UV index do you burn at?+
Fair (Fitzpatrick I–II) skin can start burning in 15–25 minutes at UV 6, and under 10 minutes at UV 9+. Deeper skin tones burn slower but still take UV damage — tanning is a damage response, not a shield. Our Fitzpatrick test tells you your sun-response type.
Can you tan or burn when it’s cloudy?+
Yes. Clouds block visible light far more effectively than UV — up to 80% of UV passes through light cloud. If the index reads Moderate or higher, cloudy still means protection.
What time is UV highest?+
Roughly 10am–4pm, peaking around solar noon (about 1pm during daylight saving). The hourly chart in this tool shows your location’s actual curve for today.
How much sunscreen should I use on my face?+
About ¼ teaspoon for face and neck — the two-finger rule (two full strips of sunscreen along the index and middle finger). Most people apply a quarter to half of the tested dose, which is why a thin smear of SPF 50 behaves like SPF 15.
Is UV higher at altitude?+
Yes — roughly 10% more UV per 1,000 meters of elevation, because there is less atmosphere above you to absorb it. Mountain snow adds reflection on top, which is how winter ski days out-burn summer beach days.
Do windows block UV?+
Standard glass blocks most UVB (the burning band) but passes a large share of UVA (the aging band). Long hours by a sunny window or in a car accumulate real photoaging exposure — the classic one-sided truck-driver photo exists for a reason.
Does a tan protect against UV?+
A tan provides the equivalent of roughly SPF 2–4 — and it is itself visible DNA damage. It neither prevents burning at high indices nor meaningfully slows photoaging.