Summer means longer days, higher temperatures and more time spent in the sun. While these can make for great times and lasting memories, they can also lead to a higher risk of sun damage.

Although you may know that wearing sunscreen is important, how much do you really know about SPF, how it works and what it helps protect against?

Understanding these things is crucial to staying as safe as possible under the summer sun, minimizing your risk of sunburns and reducing your chances of skin cancer.

The many dangers of the sun

Although many people associate being under the sun as a great way to get a nice tan, the sun can also be extremely damaging to your skin. This is because the sun gives off powerful and harmful ultraviolet (UV) rays.

UVA rays have longer wavelengths and tend to penetrate deeper into the skin, largely contributing to skin cancer, while UVB rays have a shorter wavelength, penetrating the topmost layers of skin and causing sunburns.

Exposure to UVA and UVB rays can lead to painful sunburns, which affect the topmost and potentially deeper layers of your skin. Sunburns can be painful and red, lead to peeling and can even cause blistering.

UV radiation can also cause premature aging of the skin, including fine lines and wrinkles, sun spots and discoloration. Over time, UV rays can also start to cause skin cancer, which could be life threatening.

UV rays can cause damage to your skin in as little as 15 minutes. Contrary to popular belief, short-term exposure to the sun can be dangerous—sunburns and skin cancer are not only risks for people who are outside for long periods of time. And, sun damage can build up over time, meaning preventative care is necessary as often as possible.

Additionally, UV rays are not related to temperature or even clouds. The sun can still affect you, even if the temperature is a little chilly or clouds are covering the sky.

What all of this means is that sun protection is extremely important at all times of the year, during rain or shine—but is particularly important during summer, when you’re likely to be outside more often, for longer periods of time and with less protection from clothing.

What you need to know about SPF

In order to protect your skin from the sun’s harmful rays, you’ll want to wear a sunscreen lotion that provides adequate SPF.

SPF, which stands for sun protection factor, represents the effectiveness of the protection the sunscreen provides against UV rays. When selecting a sunscreen lotion, look for an SPF of 30 or higher for adequate protection from the sun.

The higher the SPF the better—to a point. Experts aren’t convinced that sunscreens with an SPF of more than 50 are truly more effective at blocking UV rays. For this reason, using an SPF of 30 to 50 is usually adequate. You should be more concerned about applying as much and as often as necessary.

Make sure your sunscreen is broad spectrum, meaning it protects against both UVA and UVB rays, which have different effects on the skin. Many products only protect against UVB rays to help you avoid sunburns, but UVA rays could be much more dangerous over time.

Most sunscreen works by absorbing or scattering UV rays once they hit the skin’s surface, preventing them from being absorbed by your skin cells themselves.

Proper sunscreen application

In order for your sunscreen to work as best as possible to protect you from harmful UV radiation, you need to apply it correctly.

Apply one ounce of sunscreen 15 to 30 minutes before going outside. You’ll want to reapply it every two hours after that to ensure adequate protection. If you are swimming, make sure your sunscreen is water resistant and make sure you reapply every 40 or 80 minutes, depending on what the manufacturer recommends.

Don’t forget sunscreen for other parts of your body, too, like your lips, which will require a lip balm formulated with SPF. You may also want to use a specialized facial sunblock that won’t clog pores, as well as a sunscreen to protect your scalp.

Staying safe in the sun

While sunscreen is certainly a great way to protect your skin from the sun’s dangers, it can’t offer 100 percent protection. For this reason, try to stay in the shade as much as possible or wear clothing that protects your skin.

With the right combination of sunscreen and other protective measures, you’ll be ready for a full summer of fun without the threat of painful burns and a higher risk of skin cancer.