The Ultraviolet Index (UVI) is an international, scientific measure of the level of ultraviolet radiation (UVR) reaching the Earth's surface. It measures the intensity of UVR in our environment. The higher the number the more intense the UVR and the greater the need for sun protection.
UV Poster - Right click on the poster to save and print to A3 or A4
The UVI is promoted by the World Health Organization. It is scientifically based, and is used internationally. “A Practical Guide' can be downloaded from http://www.who.int/uv/publications/globalindex/en/.
Ultraviolet radiation (UVR) causes damage to our skin and can lead to skin cancer, which kills almost 400 New Zealanders a year.
The major cause of skin cancer is over exposure to UVR from the sun, particularly during childhood and adolescence. Even if exposure does not cause obvious sunburn, damage still occurs and builds up over the years.
Skin cancer can be prevented in most cases. When the UVI is at 3 or more we need to protect ourselves. This happens almost daily between September and April, and can happen in winter, especially at high altitudes and in snow. Even when the temperature is not hot the UVR levels can be dangerous so temperature is not a good indicator of the need to protect yourself. UVR can penetrate light cloud cover, so even on cloudy days, and days that may have intermittent showers, you may still be at risk.
In New Zealand UVR levels vary throughout the day. The UVR peaks at around solar noon (1.00 pm to 1.30 pm during the daylight saving months).
Find the UV level for your area:
NIWA website - click on your town/city and find out the time during the day you need to protect yourself from the sun. The diagrams show UV levels at specific times of the day and give a maximum UV level for sunny and cloudy skies.