The sun's reflective powers are 17% on sand and 80% on snow.

Even on a cloudy day 80% of the sun's UV rays pass through the clouds.

How much sunscreen should be used, and how often should it be applied?
One ounce should be applied to dry skin 15-30 minutes BEFORE going outdoors.

Coat skin liberally.

 

Pay attention to the face, ears, hands and arms.

What type of sunscreen should I use?
Should be water resistant, so they are not easily removed by sweating or swimming.
Should have an SPF of 15 or higher.

Sunscreen and SPF Numbers?

Does SPF 30 have twice as much sun protection as SPF 15?
SPF protection does not actually increase proportionately with a designed SPF number. In higher SPFs such as SPF 30, 97% of sun burning rays re-deflected, while an SPF of 15 indicates 93% deflection and an SPF of 2 equals 50% deflection.