Unless you are albino (which is a large set of other problems) being in the sun all day will develop enough of a tan that you won't sunburn. There might be a problem in spring, but by summer time most people will have spent enough time outdoors that they wouldn't sunburn. I've always been the lightest person in town (a tie in Stockholm) and I can spend all day outside without any sunscreen and I won't burn on the parts of my body normally not covered (my arms), but other parts would burn in a few minutes (If I took off my hat or shirt...)