UV Index

The UV Index predicts the levels of ultraviolet radiation on a daily basis. It is a computer model used around the world which combines multiple variables to determine the next day’s maximum UV level or to forecast peak UV hours. Some of the variables used include ozone, latitude, elevation, time of year and time of day.

Worldwide standards have been introduced to interpret the UV index. They give advice for how to protect yourself depending on your level of UV exposure. In 2004, the UV Index in America was modified to be consistent with the global standard published by the World Health Organization.

Generally the UV Index does not consider the effects of cloud cover, but will indicate it is a "clear sky day” or a "cloud free” index. Below are the ranges of UV exposure and the protections suggested for each range:

UV Range < 2 is low and no protection is required. You can safely stay outside.

UV Range 3 to 5 is moderate which require some protection. Seek shade during midday hours. Wear sun protective clothing, including a hat with a 3-inch brim and sunglasses. Apply sunscreen to all exposed skin and reapply every two hours.

UV Range 6 to 7 is high which requires protection. Seek shade during midday hours. Wear sun protective clothing, including a shirt, a hat with a 3-inch brim and sunglasses. Apply sunscreen to all exposed skin and reapply every two hours.

UV Range 8 to 10 is very high which requires extra protection. Avoid being outside during midday hours. Make sure to seek shade. Wear sun protective clothing including a shirt, a hat with a 3-inch brim and sunglasses. Apply sunscreen twenty minutes before going outside and reapply every two hours.

UV Range 11 is extreme and requires caution. Avoid being outside during midday hours. Make sure to seek shade. Wear sun protective clothing including a shirt, a hat with a 3-inch brim and sunglasses. Apply sunscreen twenty minutes before going outside and reapply every two hours.

Local television stations often provide a UV Index with their weather news. Or you can find the UV index on the internet at the Environmental Protection Agency or the National Weather Service.