UV Hour

How long can you tan in UV 11?

11 UV Index
Extreme UV

At UV 11, skin type II reaches the first redness in about 15 min with no sunscreen, and about 7 h 35 with SPF 30. Type I has 12 min; type VI has 36 min. UV 11 is in the extreme band (11+).

Equatorial noon, high-altitude tropics, and snowfields in spring — fresh snow reflects up to 80% of UV straight back at you.

Today in Columbus

UV 0 right now (low) · peak UV 8.6 at 14:00 · skin type II window 11:07–11:35 and 16:36–17:49

8.6 peak today
Very high UV
  • 14:00 Peak UV hour
  • 19 min Time to redness at peak, type II
  • 11:07–11:35 First of 2 windows
  • 11:20–17:13 Protection recommended (UV 3+, WHO)
0 2 4 6 8 10 06:00 09:00 12:00 15:00 18:00 21:00 8.6 our 40-min cut-off — UV 4.2
Your window Under 40 min to redness UV index
Today's window in Columbus, by skin type. Times are local.
Skin typeWindowTime to redness at peak UV 8.6
I17:03–17:4916 min
II11:07–11:35, 16:36–17:4919 min
III11:07–11:45, 16:13–17:4923 min
IV11:07–12:20, 15:21–17:4931 min
V11:07–13:34, 14:14–17:4939 min
VI11:07–17:4947 min

Burn times at UV 11, by skin type and SPF

Minutes of unprotected sun before the first redness, at UV 11. Below 20 minutes is shown in red.
Skin type No SPFSPF 15SPF 30SPF 50
I — Always burns, never tans. 12 min 3 h 02 6 h 04 10 h 06
II — Burns easily, tans minimally. 15 min 3 h 47 7 h 35 12 h 38
III — Burns moderately, tans gradually. 18 min 4 h 33 9 h 05 15 h 09
IV — Burns rarely, tans easily. 24 min 6 h 04 12 h 07 20 h 12
V — Burns very rarely, tans very easily. 30 min 7 h 35 15 h 09 over 24 h
VI — Almost never burns, always tans. 36 min 9 h 05 18 h 11 over 24 h

Every figure is 0.667 × MED ÷ UV, the standard erythemal formula. The MED values are the published Fitzpatrick doses: 200 to 600 J/m² from type I to type VI. See the full method.

What UV 11 actually means

UV 11 and above is the extreme band, the top of the official scale. Type I burns in about 12 minutes and type VI in 36. There is no skin type for which an hour of unprotected midday sun is reasonable at this level. It is also the level where the reflective surface under your feet can matter more than the sun above your head.

What to do: Nobody has a safe unprotected midday window at UV 11. Cover up, and treat the shade as the default rather than the exception.

Official guidance for the extreme band (11+): Unprotected skin burns in minutes. Stay indoors around midday.

Your skin type at UV 11

Where the sun is strongest right now

Nowhere we track peaks at exactly UV 11 on its current forecast day. Here is where the sun is strongest instead.

UV 11 — the questions people actually ask

How long can you stay in UV 11 without burning?

At UV 11, unprotected skin reaches the first visible redness after about 12 min for Fitzpatrick type I, 15 min for type II, 18 min for type III and 36 min for type VI. Those figures assume a clear sky, sea level, and no reflective surface.

Is UV 11 strong enough to tan?

Yes. UV 11 is in the extreme band, well above the UV 2 threshold where skin starts producing melanin. The constraint at UV 11 is not whether you can tan, it is how long before you cross into a burn — 15 min for type II.

How long can you stay in UV 11 with SPF 30?

SPF 30 multiplies the unprotected time by 30 in laboratory conditions, so type II goes from about 15 min to about 7 h 35 at UV 11. Real-world protection is usually lower because most people apply about a quarter of the tested amount, and because sunscreen comes off with water and towels.

Does cloud cover change how long you can tan at UV 11?

Less than people expect. A completely overcast sky cuts UV 11 to roughly UV 2.8; a half-covered sky cuts it by about 7%. That is why sunburn on a grey day is common — the heat drops far more than the UV does.

What is the safe UV limit for my skin type?

UV Hour uses one rule: stay below the UV level that leaves at least 40 minutes before the first redness. That gives UV 3.3 for type I, UV 4.2 for type II, UV 5 for type III and UV 10 for type VI. At UV 11, no skin type has a comfortable unprotected window.