Another way to limit exposure to UV light is to avoid being outdoors in sunlight too long. UV rays are most intense during the middle of the day, usually between the hours of 10 am and 4 pm. If you are unsure about the sun’s intensity, take the shadow test: If your shadow is shorter than you, the sun’s rays are the strongest. Plan activities out of the sun during these times. If you must be outdoors, protect your skin.
UV rays reach the ground throughout the year, even on cloudy days. UV rays can also pass through water, so don’t think you’re safe if you’re in the water and feeling cool. Be especially careful on the beach and in the snow because sand and snow reflect sunlight, increasing the amount of UV radiation you receive.
Some UV rays can also pass through windows. Typical car, home, and office windows block most of the UVB rays but a smaller portion of UVA rays, so even if you don’t feel you’re getting burned your skin may still get some long-term damage. Tinted windows help block more UVA rays, although this depends on the type of tinting. UV radiation that comes through windows probably doesn’t pose a great risk to most people unless they spend extended periods of time close to a window that receives direct sunlight.
If you plan to be outdoors, you may want to check the UV Index for your area. The UV Index usually can be found in the local newspaper or on TV and radio news broadcasts. It is also available on the EPA’s web site at
(Click on our prevention steps for more information)
Use a sunscreen with a sun protection factor (SPF) of 15 or higher.
Be sure to apply the sunscreen properly.
Wear sunglasses that block UV rays.
Limit direct sun exposure during midday.