For open water swimmers in warm weather locations, sunscreens are almost as ubiquitous as goggles and Vaseline.

With so much exposed skin, the decision on the exact type of sunscreen is based on availability, price, amount of zinc oxide, and a variety of other factor.

These are the estimated blockage of the sun’s harmful UVA and UVB rays:

SPF 2 blocks 50%
SPF 15 blocks 93%
SPF 30 blocks 97%
SPF 50 blocks 98%
SPF 70 blocks 98.6%
SPF 90 blocks 98.9%

Copyright © 2013 by Open Water Swimming