Sunburn risk time

This is not a safe time, only a rough warning. See how quickly the sun could start to redden bare skin today.

Your details

UV index
Skin type
Time you plan to be outside

Find the UV index on the Met Office forecast or a weather app, and use the highest figure for the time you will be out.

UV index 6 (high), skin II

About 22 min

of unprotected sun before skin may start to redden

  • Your planned time outside60 min, 270% of that dose
  • UV levelHigh: protect your skin
  • Skin typeType II: burns easily, tans a little
  • Sun creamSPF 30 or more, 4 or 5 star UVA, top up every 2 hours

This is a rough average from international radiation protection figures. People of the same skin type vary a lot, and sand, water, snow and altitude add more UV. It is not a safe time limit, and sun cream does not mean you can stay out longer. The NHS says protect your skin when the UV index is 3 or more, and find shade from 11am to 3pm.

Sponge sunburn with cool water and use aftersun. Get medical help if you feel unwell, or the skin swells badly or blisters. Show a GP any new or changing mole.

The working

UV index 6, skin type II

ICNIRP gives one standard erythema dose (SED) for every 1.1 hours at UV index 1, which is 0.9 SED an hour. At UV index 6 that is 5.4 SED an hour. Skin type II starts to redden from about 2 SED, so bare skin may begin to redden in roughly 22 minutes. An hour out would be about 270% of that dose.

Skin types

From ICNIRP

TypeTypical dose to redden
Iunder 2 SED
II2 to 3 SED
III3 to 5 SED
IV5 to 7 SED
V7 to 10 SED
VIover 10 SED

We use the lower end of each range, so the time is on the cautious side.

Protecting your skin

NHS advice

  • Protect your skin when the UV index is 3 or more
  • Spend time in the shade between 11am and 3pm, March to October
  • Cover up with clothing, a hat and sunglasses
  • Use at least SPF 30 with 4 or 5 star UVA protection, and do not rely on sun cream alone
  • Keep babies under 6 months out of direct strong sunlight

Read with care

What this cannot tell you

  • Give a safe timeSkin damage can happen before you see redness.
  • Know your skinPeople of the same type vary a lot.
  • Count reflectionSand, water, snow and altitude add more UV.

Questions

Common questions

How long does it take to burn at UV index 6?

For fair skin that burns easily, redness may start in roughly 20 minutes. Darker skin takes longer, but all skin can be damaged.

What UV index needs sun cream?

The NHS suggests protecting your skin when the UV index is 3 or higher.

Can I still burn on a cloudy day?

Yes. The NHS says you can burn in the UK even when it is cloudy, so check the UV index rather than how sunny it looks.

Does darker skin need protection?

The NHS says naturally brown or black skin has some protection, so skin cancer is less likely, but skin can still be damaged. Sunburn may not show as redness on darker skin.

Sources

Last checked 21 October 2026. Spotted something wrong? Tell us and we will fix it.

When to get help

A pharmacist can help with mild sunburn. Ask for an urgent GP appointment or get help from NHS 111 if skin is blistered or swollen, you feel hot, cold or shivery, very tired, dizzy or sick, or a baby or young child has sunburn. See a GP about a mole that changes shape, size or colour.

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