TL;DR
The Met Office UV index runs from 0 to 11-plus and indicates UV strength. Levels of 6 or 7 are typical at UK midday in summer. The forecast supports skin cancer prevention guidance from the British Association of Dermatologists and Cancer Research UK.
The Met Office publishes a UV index forecast for every UK region, running from 0 to 11-plus on a standard international scale. Levels of 6 or 7 are typical at UK midday in summer, and the forecast supports skin cancer prevention guidance issued by the British Association of Dermatologists and Cancer Research UK.
How the UV index is calculated
The UV index is a measure of UV radiation reaching the surface, taking into account the sun's angle, the time of year, latitude, altitude and cloud cover. The international standard runs from 0 to 11-plus.
Levels 1 to 2 are low, 3 to 5 moderate, 6 to 7 high, 8 to 10 very high and 11 or above extreme. Higher numbers mean more UV reaches the skin per minute of exposure.
Typical UK UV index values
In the UK, UV index typically peaks at 6 or 7 in midsummer at midday. Spring and autumn rarely exceed 4 or 5. Winter midday values are usually 1 or 2.
Within a single day, UV usually peaks between 11am and 3pm. Cloud cover reduces UV but does not eliminate it; reflective surfaces such as water and white sand can increase exposure.
Sun safety advice by index level
At index 3 to 5, sunscreen of SPF 15 to 30 is recommended for prolonged outdoor exposure. At index 6 to 7, SPF 30 or higher, a hat and sunglasses are advised, with shade between 11am and 3pm.
At index 8 to 10, extra precautions are needed including covered clothing, broad-brimmed hats and avoiding direct sun during peak hours. Index 11-plus calls for the maximum protection and minimal direct exposure.
Skin cancer risk and vitamin D balance
Skin cancer is the most common cancer in the UK and most cases are linked to UV exposure. Cancer Research UK publishes ABCDE guidance on mole self-checks: Asymmetry, Border irregularity, Colour variation, Diameter over 6mm and Evolving features.
Short periods of unprotected exposure produce vitamin D. NHS guidance suggests 10 to 15 minutes of exposure to bare skin around midday between April and September is enough for most adults, with a 10 microgram supplement during autumn and winter.
Where to find the UV forecast
The Met Office app and weather pages on metoffice.gov.uk publish the daily UV index for every UK region. The forecast updates daily and includes a seven-day outlook for planning weekend activity.
Smartphone weather apps that source data from the Met Office, including default Apple Weather and Android weather widgets, also show the UV index. Sunscreen brands' own apps often track exposure but should be cross-checked with the Met Office figure.
Key facts
- UV index runs from 0 to 11-plus.
- UK midsummer midday typically reaches 6 or 7.
- Index 6 or above warrants SPF 30 or higher.
- Cloud cover reduces but does not eliminate UV.
- Cancer Research UK ABCDE mole check applies all year.
FAQ
What does the UV index actually measure?
UV radiation reaching the surface, taking into account the sun's angle, time of year, latitude, altitude and cloud cover. The international standard runs from 0 to 11-plus.
How high does UV go in the UK?
Typically 6 or 7 at midday in midsummer, classed as high. Spring and autumn rarely exceed 4 or 5. Winter midday values are usually 1 or 2.
What SPF should I use?
SPF 30 or higher with four or five star UVA protection is recommended at UV index 6 or above. Generous application matters because most people apply less than the test conditions assume.
Does cloud cover protect me?
Cloud reduces UV but does not eliminate it. You can burn on cloudy days, particularly during high-UV periods. Reflective surfaces such as water and white sand can also increase exposure.
