This problem is important for nothern people especially, cuz it's very hard for our body to protect oneself from the sun. I am a northern slav and I live in tropic Portugal, so I will share my secrets how I protect myself in the summer.
Physical protection. In hot sunny weather it's better to wear light colored clothing and forget about the dark one. Why? Because of physical factors. Black color absorbs radiation, while white reflects it. So if you dress a bright blouse made of a natural fabric (it's another important factor, only the natural materials are a natural "climate control" of your body), you'll feel much better than in the dark and synthetic ones. And, mindful of the ability of the natural fabrics to keep own microclimate, it's better to be dressed than naked under the scorching sun. Otherwise, the sun will dry the skin's surface fast, and you will get a sunstroke.
Don't forget to protect the head. I have a problem: I want the color of my hair naturally fades out in the sun, but without hat I can get the sunstroke! In this case, it's better to use hats with holes for hair or bandanas. You can cover the head, and pull the hair outside =) There will be as a natural bleaching for your hair, as well a good protection from the sunstroke.
Also you need to use the protection of cosmetic. The main thing for us to understand the difference between UVA and UVB-filters in cosmetic stuffs. UVB-filters protect against radiation, which affects only the surface of the skin (making the suntan, causing burns, influencing on a pigmentation), but UVA-filters are more important. They protect from solar radiation, which affects on the deepest layers of the skin, causing devastating effects and a premature aging. For example, window glass protects us only from the B-rays. So if you don't close curtains, you expose the skin to the aging. And we don't get suntun but get older outwardly. That's why it's very important that our arsenal of a protective equipment and daily cosmetics contains UVA-filters. My sunscreen with SPF +50 of Piz Buin Allergy contains both types of filters as UVB as well UVA. So I don't care =) And after the sun I use SOS After Sun of Nivea Sun. I chose this because of my pale skin burns on the south immediately if even I go to bring off a garbage for a couple of minutes:D
Speaking of degrees of the sunscreen protection, remember that the smallest protection is +10 is intended for dark-skinned people, but if you have pale skin as a gift from nordic ancestors, you need +50. If your are in the city, you can use more low protection, on the southern resorts you can't survive without high protection. Because the southern sun is the most ruthless.
There are a few secrets of how to protect oneself from the sun.
1. Stay away from water. The open water reflects solar radiation, so on the coast or near of fountains you can get a "double portion" of the sun.
2. Even in cloudy weather you have a risk to get burns. Because the clouds are not the most reliable UV-filter. Protect yourself even in cloudy weather.
3. If you have an opportunity use the sunbeds on the beach . Lying on the sand it's very easy to overheat oneself because the "layer" of hot air is above the sand. It dries you up from inside and outside.
4. Use towels after bathing . In hot weather it's tempting to stay wet, and prolong the pleasure of a coolness. But the sun passing through the droplets of water on your skin, is creating microburns of your skin.
5. Sun can burn not only the skin but eyes too. If you don't protect the eyes, the burning of the cornea doesn't take a lot of time. Choose high-quality sunglasses with a degree of protection "High UV-Protection". Also remember that the glasses should protect your eyes and the skin around "in all directions": to have and UVB, and UVA-filters.
Take care of your beauty! Big kisses to you! I love you very much! Meaow=*