This summer is hotter than ever, and all we really want is to cool down. It’s no wonder why our weekends and holidays are suddenly dedicated to beach trips and pool parties. These really are the best ways to beat the heat, not to mention are loads of fun, until someone come home with a bad sunburn. The reality is most of us forget that applying sunscreen (and reapplying after every two to three hours) is an essential part of our trips and should be used continuously every day.

If you think about it, a sunburn isn’t just a minor burn that goes away—it has long-term, irreversible effects on our skin that can lead to premature aging and even skin cancer. This is actually pretty serious. The sun’s rays are more dangerous than ever, as they deliver three types of radiation: UVA has known to cause premature wrinkles, uneven pigmentation and sagging skin; UVB results in skin reddening and painful sunburns; and UVC rays leads to the formation of skin radicals.

We need sunscreen that protects us from all three types of radiation, and that is where SPF comes in. In case you didn’t know, SPF stands for Sun Protection Factor, and is actually the measured ability of a sunscreen to protect the skin. This is not an amount of protection, but an indication of how long it will take for UVB rays to redden your skin, as compared to if you didn’t apply sunscreen. For example, an SPF of 15 will take your skin 15 times longer to burn than without the sunscreen.