|
Exposure
Category |
Index Number
|
Sun Protection Messages
|
|
LOW
|
<2
|
You can safely enjoy being outside. Wear
sunglasses on bright days. If you burn easily, cover up and use
sunscreen SPF 15+.
In winter, reflection off snow can nearly double UV strength. |
|
MODERATE
|
3-5
|
Take precautions if you will be outside, such as wearing a hat and sunglasses and using sunscreen SPF 15+. Reduce your exposure to the sun's most intense UV radiation by seeking shade during midday hours. |
|
HIGH
|
6-7
|
Protection against sun damage is needed. Wear a wide-brimmed hat and sunglasses, use sunscreen SPF 15+ and wear a long-sleeved shirt and pants when practical. Reduce your exposure to the sun's most intense UV radiation by seeking shade during midday hours. |
|
VERY HIGH
|
8-10
|
Protection against sun damage is needed.
If you need to be outside during midday hours between 10 a.m. and 4
p.m., take steps to reduce sun exposure. A shirt, hat and sunscreen are
a must, and be sure you seek shade. Beachgoers should know that white sand and other bright surfaces reflect UV and can double UV exposure. |
|
EXTREME
|
11+
|
Protection against sun damage is needed.
If you need to be outside during midday hours between 10 a.m. and 4
p.m., take steps to reduce sun exposure. A shirt, hat and sunscreen are
a must, and be sure you seek shade. Beachgoers should know that white sand and other bright surfaces reflect UV and can double UV exposure. |
What is the nature of UV radiation?
How does UV radiation vary throughout the day?
How do clouds, elevation, surface type (albedo) and aerosols (haze) affect UV radiation?