At 46, I guess I have a little bit of sun experience!!
Anyways, I lived in So.Cal.--Fullerton and Yorba Linda--from 1983 to 1993. I grew up in Wisconsin and returned to Wisconsin--not because of the sun, but for the snow!! Really, I moved back mostly because of family and work choices. Which should be your only reason for moving, not the sun!!
I agree that the sun is different in different locations. I just returned from a trip to see my almost 91 year old grandma in nebraska. Now that is some bright sun!! Of course, nothing in the way to block or alter it, just lots and lots of corn!
I am with the others on sunburns--mine have all been due to arelessness and stupidity on my part. I haven't had a serious burn in many years, but i do manage to get one sunburn a year due to stupidity--like getting burned on cloudy days or while under a shady tree--yep, I know it will happen, but I always get careless in those situations. However, I can go to a waterpark from open to close in mid July in bright sunlight and not even turn pink! Hat, sunblock and a Tshirt over the swimsuit were the answer!
I also don't wear sumblock everyday. I wear it when I am going to be spending time outside, but not just to go to and from work--walking four blocks each way to the bus, or for running errands. When I am doing outdoor activiies--hiking, biking, camping, whatever, I prefer hats to sunglasses, although I do own a pair, and use them when I need to. I had a major aversion to them as a child, and still have problems with them causing my vision to be worse, but that's just me.
There are loads of pictures of me as a kid in which I am looking down when outside, it is just a natural reaction to the brightness. I don't remember the sunlight actually being painful, even now it rarely is--only when I am riding in a car directly into the sunset, etc.
I love the water, and that is an issue with the sun. Some of the danger areas on the body that tend to get burned=, due to reflection from the water, are the eyelids, under your nose, under your chin, under your ears, the backs of your legs/knees when you are in a boat--especially a nice silver canoe--etc. Ears in general if you don't wear a hat with a brimall the way around and forget the sunblock.
I, too, know how much sun is enough. I can't tell you a precise number, because it varies by location and activity. It's just something you learn with experience, just like as a mom you soon learn to tell if your child has a fever and whether it is high enough to worry about without ever getting out a thermometer.
My advice would be to enjoy all the activities you always have done, but take it in smaller doses at first and experiment with different hats, sunglasses and sunblocks until you find the combination that works and can judge when he has had enough. Soon enough, your kid will be able to tell you!
Joni