You may agree that these are great reasons to get to the beach super early - like before 9am! While the reasons I mention are good ones the best reason of all is that it's a good idea to get your naked skin out of the sun between 11am and 4pm.
It's easy to forget that our sun is more harsh these days than it was 10 or 15 years ago. I remember as a kid not having to pay as much attention to the sun's ravaging rays; I guess the scientists who made such a big thing of the depletion of the atmosphere's ozone layer had a point. :(
I'm not partial to leathery skin, I don't relish the thought of skin cancer, and I kinda like the look of untanned skin - which is why I always use SPF30+ sunscreen when spending time outdoors. If you don't already, it's probably a good idea for you to do the same. :)