UV index 1: how long until skin burns?
UV index 1 falls in WHO's Low category. Without protection, very fair skin (type I) can start to redden in about 100 minutes, and olive skin (type IV) in more than 2 hours. These are rough estimates, not safe times.
Low · 1–2 Low risk for most people; take care on snow, water or mountains.
A warning, not a safe time. Redness shows up hours later.
Minutes to first redness by skin type
| Type IAlways burns, never tans; very pale skin, often freckles or red hair | about 100 minutes |
|---|---|
| Type IIUsually burns, tans with difficulty; fair skin, often light eyes | more than 2 hours |
| Type IIISometimes burns, tans gradually; light to light olive skin | more than 2 hours |
| Type IVRarely burns, tans easily; olive or light brown skin | more than 2 hours |
| Type VVery rarely burns, tans darkly; naturally brown skin | more than 2 hours |
| Type VIAlmost never burns; naturally dark brown to black skin | more than 2 hours |
What WHO advises at this level
WHO says the risk of UV damage at this level is limited, even for very fair skin, and under normal conditions you need no special protection. Watch for exceptions: fresh snow, water and high altitude add a lot of UV, and some medicines make skin far more sensitive. In those situations, cover up and wear sunglasses.
When and where you see this level
UV 1 is typical of winter at mid and high latitudes: in northern and central Europe it is often the midday peak from November to January. Elsewhere you see it early in the morning, late in the afternoon or under heavy cloud.
What this means if you want a tan
At UV 1 there is very little sunburning UV, so your skin will tan very slowly, if at all. That does not make long sunbathing harmless: a tan is the skin's response to UV damage, and hours outside still add to your lifetime dose.
Frequently asked questions
How long does it take to burn at UV 1?
Rough estimates for unprotected skin at UV 1: type I: about 100 minutes; type II: more than 2 hours; type III: more than 2 hours; type IV: more than 2 hours. Redness usually appears hours later, and some people burn sooner. These are not safe times.
Is UV 1 high?
Low (1–2). WHO says the risk of UV damage at this level is limited, even for very fair skin, and under normal conditions you need no special protection. Watch for exceptions: fresh snow, water and high altitude add a lot of UV, and some medicines make skin far more sensitive. In those situations, cover up and wear sunglasses.
Can you tan at UV 1?
At UV 1 there is very little sunburning UV, so your skin will tan very slowly, if at all. That does not make long sunbathing harmless: a tan is the skin's response to UV damage, and hours outside still add to your lifetime dose.
Sources
- WHO, WMO, UNEP, ICNIRP (2002): Global Solar UV Index – A Practical Guide
- WHO (2022): Radiation – The ultraviolet (UV) index, questions and answers
- ICNIRP with ILO and WHO (2007): Protecting Workers from Ultraviolet Radiation (skin types and SED, Table 1)
- Journal of Cosmetic Dermatology: Fitzpatrick skin phototypes with typical minimal erythema dose (Table 1, after Fitzpatrick 1988 and Pathak 1987)
- CIE: Standard Erythema Dose, a Review (1 SED = 100 J/m²)