SunkatUV index 1: how long can you tan before you burn?
UV 1 is in the low band. Here is how long each skin type can stay out, and what it means for tanning.
Short answer: at UV 1, skin starts to redden without sunscreen after about 2 h 13 min for very fair skin (type I), 2 h 46 min for fair skin (II), 3 h 20 min for medium skin (III) and 5 h+ for olive skin (IV). The Sunkat app keeps a tanning session to 50 minutes per side for fair skin and 60 for medium skin, so you stop well before that.
Minutes at UV 1 by skin type
| Skin type | First redness no sunscreen | Sunkat limit per side | with SPF 30 | with SPF 50 |
|---|---|---|---|---|
| Type I very fair, always burns, never tans | 2 h 13 min | 33 min | 49 min | 57 min |
| Type II fair, burns easily, tans a little | 2 h 46 min | 50 min | 60 min | 60 min |
| Type III medium, sometimes burns, tans gradually | 3 h 20 min | 60 min | 60 min | 60 min |
| Type IV olive, rarely burns, tans easily | 5 h+ | 60 min | 60 min | 60 min |
| Type V brown, very rarely burns | 5 h+ | 60 min | 60 min | 60 min |
| Type VI dark brown to black, almost never burns | 5 h+ | 60 min | 60 min | 60 min |
First redness = minimal erythema dose ÷ (1.5 × 1), using the lower end of each skin type's range. The Sunkat limit is the app's conservative session length per side, capped at 60 minutes. How the numbers are calculated.
Can you tan at UV 1?
Barely. At UV 1 the dose builds so slowly that most people will not redden or see a tan after a normal outing, and WHO says you can stay outside with minimal protection at UV 1 and 2. Very fair skin can still redden on a long day (type I needs about 2 h 13 min of steady exposure), especially near snow or water, which reflect UV back at you.
When and where you see UV 1
UV 1 and 2 are typical of northern Europe from November to February, of early mornings and late afternoons in summer, and of heavily overcast days.
UV changes through the day. The forecast number in your weather app is usually the midday peak, so a morning or late-afternoon session runs at a lower UV and takes longer to reach the same dose.
Other UV levels
Frequently asked
How long does it take to tan in UV 1?
There is no fixed number of minutes, because a tan shows up 2 to 3 days after exposure as your skin makes more melanin, not during the session. What you can control is staying under your burn limit: at UV 1 the Sunkat app's limit is 50 minutes per side for fair skin and 60 for medium skin, well before fair skin starts to redden at about 2 h 46 min.
How long until you burn in UV 1?
Without sunscreen, the first redness appears after about 2 h 13 min for type I skin, 2 h 46 min for type II, 3 h 20 min for type III and 5 h+ for type IV. These are earliest-likely times from the WHO UV index definition and published minimal erythema doses.
Do you need sunscreen at UV 1?
Usually not for a short time outside. WHO puts UV 1 and 2 in the low band where minimal protection is needed. Very fair skin spending hours outside, or anyone on snow or water, should still use sunglasses and SPF.
Can you burn at UV 1 with SPF 50?
Yes. SPF 50 only reaches its label protection with about 2 mg/cm² of sunscreen, roughly a teaspoon for each arm, and most people apply a quarter to half of that. Sweat, water and towels also remove it, so reapply at least every two hours and after swimming.
Know your minutes at UV 1, and every other UV
Sunkat reads the live UV where you are, times each side for your skin type, and tells you when to flip and when to stop. Free on iPhone and Android.
