1 hour before sunset and one hour before sunrise the UV level throughout the world is at a safe level for most people. The UV level is 2 or less in hawaii or Cleveland or anywhere. If you are still worried though , there are UV test strips that indicate the UV level if you are interested in knowing.UV might be a factor at other periods of the day but consider this:
http://mintaka.sdsu.edu/GF/vision/Galileo.html
Check the following links to find the UV level in your area: