UV Hour

How long can skin type IV tan without burning?

6.7 your limit
High UV

Fitzpatrick type IV (burns rarely, tans easily) reaches the first redness after about 33 min at UV 8 and 53 min at UV 5, with no sunscreen. Its safe ceiling is UV 6.7 — above that, there is no unprotected midday window.

Olive or light brown skin, dark hair, dark eyes.

Today in Columbus

UV 0 right now (low) · peak UV 8.6 at 14:00 · skin type IV window 11:07–12:20 and 15:21–17:49

8.6 peak today
Very high UV
  • 14:00 Peak UV hour
  • 31 min Time to redness at peak, type IV
  • 11:07–12:20 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 6.7
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

Type IV at every UV level

Minutes before the first redness for skin type IV (MED 400 J/m²), at each UV level. Below 20 minutes is shown in red.
UV index No SPFSPF 15SPF 30SPF 50 Band
UV 1 4 h 27 over 24 h over 24 h over 24 h Low
UV 2 2 h 13 over 24 h over 24 h over 24 h Low
UV 3 89 min 22 h 13 over 24 h over 24 h Moderate
UV 4 67 min 16 h 40 over 24 h over 24 h Moderate
UV 5 53 min 13 h 20 over 24 h over 24 h Moderate
UV 6 44 min 11 h 07 22 h 13 over 24 h High
UV 7 38 min 9 h 31 19 h 03 over 24 h High
UV 8 33 min 8 h 20 16 h 40 over 24 h Very high
UV 9 30 min 7 h 24 14 h 49 over 24 h Very high
UV 10 27 min 6 h 40 13 h 20 22 h 13 Very high
UV 11 24 min 6 h 04 12 h 07 20 h 12 Extreme

Rows up to UV 6.7 are the levels where type IV keeps at least 40 minutes before the first redness. How this is calculated.

What type IV actually means

At 400 J/m², type IV has double the tolerance of type I and a limit of UV 6.7. On a British summer day the window is continuous from morning to evening. At UV 8 and above it splits, like everyone else’s.

How to recognise it: Type IV rarely burns and browns quickly and evenly. Common around the Mediterranean, the Middle East and parts of Latin America.

What to do: The useful number for type IV is not the burn time, it is the ceiling: UV 6.7. Below it, plan nothing. Above it, plan the midday.

Where type IV sits among the six

Where the sun is strongest right now

Skin type IV — the questions people actually ask

How long can skin type IV stay in the sun?

It depends entirely on the UV index, not on the temperature or the season. Type IV has a minimal erythemal dose of 400 J/m², which gives about 89 min at UV 3, 53 min at UV 5, 33 min at UV 8 and 24 min at UV 11, with no sunscreen and a clear sky.

What UV index is safe for skin type IV?

Up to UV 6.7. That is the level at which type IV still has 40 minutes before the first redness — the threshold UV Hour uses everywhere. UV 6.7 sits in the high band, so on days above that, type IV gets a morning window and an afternoon window instead of one continuous one.

Am I skin type IV?

Olive or light brown skin, dark hair, dark eyes. Burns rarely, tans easily. Type IV rarely burns and browns quickly and evenly. Common around the Mediterranean, the Middle East and parts of Latin America.

How much does SPF 30 change things for type IV?

At UV 8 it takes type IV from about 33 min to about 16 h 40 in laboratory conditions. In practice the two-hour reapplication rule arrives first, so treat SPF 30 as removing the burn deadline rather than extending it to a specific new time.