We all know the importance of applying sunscreen throughout the year in order to protect our skin from UV rays. But how often should you reapply sunscreen after that initial anointment first thing in the morning?

It's a detail that's really important to get right, and it can make all the difference in how well your skin is protected in both the short and long term. Here we take a look at a few common, everyday scenarios and how often you should apply sunscreen for each of them.

When Wearing Lightweight Layers

When you're fully dressed in clothes, you probably don't really think too much about how often you should apply sunscreen. But there are a few scenarios where this is necessary, like in the summer months or when you're on vacation and dressed in beach cover-ups and lightweight layers that don't block out the sun completely.

As a main rule of thumb, if you can hold a piece of clothing up to the light and see through it, UV rays will penetrate it. This means that you'll need to wear sunscreen underneath and re-apply it every two hours throughout the day, even though you're covered up. Don't forget that this still applies after 5 p.m. in the summer or when you're visiting a destination that has particularly intense sunlight.

The American Cancer Society also recommends thinking about your location and its altitude, especially when you're traveling. Why? UV strength can increase 10 to 12 percent with every 1,000 meters that you travel above sea level, as you're closer to the sun.

When Swimming and Exercising

If you enjoy exercising in the water—whether it's canoeing, paddleboarding, or open-water swimming—you'll need to protect your skin from the sun. Being in the water doesn't offer you the protection you might think, and the parts of you above the water may actually be getting a double dose of UV, as the surface of the water actually reflects the sun's damaging rays back up at you.

Once you've liberally applied sunscreen before getting into the water, it's important to check how long you're protected once your skin gets wet. According to the American Cancer Society, no sunscreen is completely waterproof or sweat-proof, so reapplying is the best way to protect your skin. EltaMD UV Sport Broad-Spectrum SPF 50, for example, is water-resistant for up to 80 minutes. Of course, if you're in and out of the water and rubbing yourself dry each time with a towel, you need to reapply more often.

The same rule also applies to general exercise, like during a morning bike ride or a run where your face, arms, and chest are exposed to UV. You should apply liberally 15-30 minutes before you head out, reapplying again after excessive sweating, showering, or towel drying.

When Outside on Overcast Winter Days

Long-wave UVA makes up 95 percent of the rays that reach the Earth's surface and is responsible for deep structural aging of the skin. And, unlike UVB whose strength is lessened by cloud and gray skies, UVA poses a threat to the skin all year round—even on overcast winter days when the sun seems like a distant memory.

But how much and how often should you apply sunscreen in winter? Most Dermatologists recommend applying around a teaspoon-sized amount of sunscreen to the face and neck first thing in the morning. If you then spend the majority of your day outside, you should aim to reapply every two hours. While that may seem like a real chore, skin care brands have been quick to solve the problem. New sheer mists like EltaMD UV Aero Broad-Spectrum SPF 45 go on quickly and easily but still create that protective shield.

When in Transit

How often should you reapply sunscreen when traveling? It may not be an activity you'd think would require sunscreen, but if you're partial to a window seat on a plane, train, bus, or car, it's vital to lather up. In the same way that UVA rays can penetrate clouds on dreary days, they can also pierce through that glass window. In fact, your skin is more at risk for skin damage when you fly than when you travel on the ground.

This is because you're much closer to the ozone layer where the sun's rays are far more harmful when flying. So, if the majority of your flight is during the day, you should apply sunscreen every couple of hours, especially if you enjoy gazing out of the window to take in the panoramic views. Make sure you pack a TSA-approved travel-size bottle of sunscreen in your in-flight bag and re-apply as necessary.

A Pleasure, Not a Chore

While you may be surprised to discover just how often you need to reapply sunscreen, it hopefully doesn't instill the same dread as it may have a few years ago. Thankfully there are now a whole host of sunscreen formulas available, like those at EltaMD, that are not only effective at protecting the skin from harmful UV rays but also pleasurable to apply as a soothing moisturizer.

Take your time finding the right sunscreen formula and texture for your skin type—whether oily, dry, acne-prone, or combination—and you'll never find applying it a chore again.

Author

  • Catherine Hufton is a UK-based freelance journalist and writer who has worked for some of fashion's most iconic companies and written for the world's best known magazines and newspapers. Beginning her career at Net-a-Porter and Matches Fashion over 12 years ago, she has created content for L'Oréal, Elle, Harper's Bazaar, The Telegraph and more.