Hold a layer of clothing up to the light (or a day-lit window). How much sunshine can you see passing through?
This isn’t a perfect test, but it can be a good indicator of how protected clothing will be against the sun’s harmful UV rays.
The more light that passes through the fabric, the less effective the clothing will likely protect you from sun exposure.
Ultraviolet Protection Factor Ratings
You are probably familiar with the SPF ratings on sunscreens and cosmetics. SPF is a measure of sun protection against ultraviolet B (UVB) rays, which are more energetic (and more dangerous) than the (also harmful) ultraviolet A (UVA) rays. Unless your sunscreen is specifically labeled as ‘broad spectrum,’ it will only protect against UVB.
UPF – ultraviolet protection factor – is used on clothing and measures the blockage of both UVA and UVB rays.
UPF 50 means that the fabric allows 1/50th (2%) of the sun’s ultraviolet radiation to penetrate the clothing and affect your skin. An ordinary, white cotton t-shirt is typically only about UPF 5, which means that 20% of that skin cancer-causing sunlight will go through to your skin.
The type of fabric, the thickness, color, and age of the garment all affect how much light passes through. And when clothes get wet, they tend to provide significantly less protection.
Keep Yourself Safe in the Sun
You can reduce your risk of skin damage and skin cancer by taking a few simple precautions:
Seek out UPF-rated clothing. Not all garments are labeled, but more and more brands are producing clothing with added ultraviolet protection mixed in.
Add sun-protecting detergent to your laundry cycle. This process will add colorless protection to the clothing you already own.
Wear wide-brim hats to cover your face and neck. These areas are especially vulnerable to sun damage.
Limit your exposure to the sun. Stay in the shade, especially when the sun’s rays are most intense – between 11 am and 3 pm.
Put sunscreen on any area that is not covered by sun-protective clothing. If your clothes are not sufficiently protective, apply sunscreen to your skin underneath.
Use sun protection even on cold and cloudy days. The sun’s UV rays easily pass through clouds and can burn and damage your skin.
Clothing that protects you from the sun can effectively reduce your risk of skin damage, but not all clothing has the same protective quality. When looking for clothing with ultraviolet protection, look specifically for garments labeled with a UPF number and a Skin Cancer Foundation seal of recommendation.