One of the outdoors' greatest joys is basking in the sun's soft, warm glow. But, like so many of life's pleasures, it's best done in moderation. Sunlight includes rays of ultraviolet (UV) radiation, which can lead to sunburn, premature skin aging and skin cancer with exposure.
Choosing clothing that's designed for sun protection and tested to confirm its Ultraviolet Protection Factor (UPF) will give you greater control over your total level of UV exposure and can keep your skin safer.
This article will cover:
- Who can benefit from wearing UPF clothing (spoiler: pretty much everyone)
- When to wear UPF clothing
- What UPF ratings mean
- Factors that reduce and enhance sun protection
- UPF clothing materials
- UPF clothing features
- Sun protection beyond UPF clothing
If you learn nothing else about UPF, consider this: Always look for a garment's lab-tested UPF rating (if it's available) to evaluate its true UV protection level. That said, if an item doesn't have a UPF rating, there are a few things to look for when considering your options for sun protection:
- Darker fabrics usually provide more UV protection than lighter ones.
- Denser weaves provide more UV protection than looser weaves.
- Polyester and nylon offer more sun protection than natural fibers.
- Coverage matters too; perhaps it goes without saying, but garments that cover more of your skin will provide more sun protection.
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Who Can Benefit from UPF Clothing
Everyone, regardless of activity or season, will benefit from choosing apparel with sun-protecting UPF coverage. “While most people associate sun protection with hot, sunny days,” says Sandy Flint, senior materials manager with Stio, “UV exposure is a concern in both warm and cold conditions, especially at high elevations.” While UPF-rated clothing enhances everyone's protection against UV-related health risks, it is especially helpful for:
- People who are sun sensitive: People with skin that burns or freckles easily are more vulnerable to UV rays. A variety of factors can make someone more susceptible to sunburn, including skin with lighter pigmentation or a large number of moles.
- People with darker skin pigmentation: On one hand, darker pigmentation indicates the presence of more melanin, a compound that offers UV protection. But darker pigmentation also makes UV damage harder to spot—and can lull you and your doctor into being less vigilant.
- Children and older adults: Kids have relatively thin, sensitive skin, and any damage to it at an early age increases the risk of serious problems later in life. Skin damage also builds up over time, increasing the health risk for all adults as they age.
- People at high elevations, in equatorial regions, or on snow or water: UV radiation intensity is greater where the air is thinner (high elevations), where the sun is more directly overhead and UV rays have a shorter path to you through the atmosphere (equatorial regions) and where rays come both from overhead sunlight and reflected surfaces (like snow and water).
- People taking medications: Sun sensitivity is increased by a wide range of drugs, including acne treatments, antihistamines, antibiotics, certain anti-inflammatories and even herbal supplements. Double-check all your medications for cautions about the sun.
When to Wear UPF Clothing
Just as UPF clothing is beneficial for pretty much everyone, it’s also beneficial for pretty much any form of outdoor recreation—no matter the season. “UPF gear is great for many activities, from thru-hiking to split-boarding and beyond,” explains Corey Simpson, head of product communications at Patagonia. “Any activity that includes sustained sun exposure could benefit from UPF gear.”
What UPF Ratings Mean
Flint calls out three terms that shoppers should understand ahead of making a purchase:
UV-blocking garments have been lab-tested to provide specific UPF protection. The material actively prevents a significant percentage of UV radiation from hitting your skin.
"UV-resistant" refers to a material’s resistance to degradation from UV exposure.
"UV-protective" is a general term that suggests a garment provides some protection against UV rays.
For a garment to earn a UPF rating, it must pass several standardized tests, Simpson says. It's similar to SPF (Sun Protection Factor), the rating system used for sunscreen products. SPF pertains only to a sunscreen's effectiveness against UVB rays, considered to be the more damaging type of light. UPF, though, gauges a fabric's effectiveness at filtering both ultraviolet A (UVA) and ultraviolet B (UVB) light.
When you shop, things are relatively simple: Look for a higher UPF rating number and greater skin coverage in order to get better sun protection.
UPF Rating | Protection Category | Effective UV Transmission |
|---|---|---|
15 | Minimum | 6.7 |
30 | Good | 3.3 |
50+ | Excellent | 2.0 |
A UPF rating of 30 indicates the fabric of a garment will allow 1/30th (roughly 3%) of available UV radiation to pass through it. A garment rated UPF 50 permits only 1/50th (roughly 2%) UV transmission. Any fabric that allows less than 2% UV transmission is labeled UPF 50+.
Why you don't see ratings below UPF 15: Fabrics rated below UPF 15 are not considered UV-protective. A typical white cotton T-shirt, for example, offers about a UPF 5 rating, which means that 1/5th (roughly 20%) of available UV radiation passes through it.
Factors that enhance UPF ratings: As a shopper, simply look for the UPF rating on garment hangtags or labels. Clothing makers will already have considered the following factors in trying to achieve that level of sun protection:
- Construction: “Less space between yarns,” says Flint from Stio, “means fewer UV rays can pass through.” Thus, fabrics with dense, tight construction result in less UV light exposure. Other construction details being equal, thicker, heavier fabrics may have reduced UV transmission versus thinner ones, though it will likely come at the cost of breathability.
- Color: Generally, darker colors prevent more rays overall (including UV rays) from reaching your skin. Within the same color, more saturated hues outperform paler ones.
- Treatments: Chemicals and dyes that are effective at absorbing UV light can be applied during the garment’s dying or finishing process to enhance UPF. Titanium dioxide or zinc oxide coatings, for example, are mineral-based additives that reflect/scatter UV light similar to sunscreen ingredients.
- Fiber type: Polyester does an excellent job at disrupting UV light, as does nylon. Wool and silk are moderately effective. Cotton, rayon, flax and hemp fabrics often score low without added treatments.
Factors that reduce the effectiveness of UPF-rated clothing: Whether you're considering the UPF spec on new clothing or packing your favorite rashguard for a trip to the beach, be aware of the following:
- Fabric wetness: For many types of materials, wetness can cause a significant reduction in a fabric's UPF rating. Some studies, though, suggest that polyester may actually protect slightly better when wet.
- Fabric wear: As a fabric becomes worn or faded, it also becomes less effective at blocking UV light.
- Fabric stretch: Stretched fabric can lose a significant amount of its UPF, so consider replacing any item that simply fits too tightly.
How laundering affects UPF ratings: Washing your clothing can either increase or decrease its UPF, depending on several factors:
- Detergents with brighteners: While most detergents contain them and most brighteners do enhance UPF, there's no way to tell for certain if a given detergent will enhance your garment's rating.
- Shrinkage: All else being equal, shrinking a garment gives it a tighter weave, which can increase its UPF.
- Clothing that relies on finishes for its UPF rating: Finishes can vary in durability. If a finish washes out, UPF diminishes. Check to see if your garment states that its UPF rating is good for a specific number of washes.
- Clothing that relies on inherent fabric properties for its UPF rating: UPF should remain relatively unchanged as a result of washing—until it diminishes simply because the fabric becomes worn or faded.
Read more: How to Pick the Most Breathable Fabrics, What Is Merino Wool?
UPF Clothing Materials
Outdoor apparel can be made with many different materials, each of which offers slightly different protection from UV light, says Flint. In hot weather, he recommends looking for UPF garments that are lightweight with moisture-wicking benefits. In cold weather on the other hand, seek out UPF-rated merino wool and synthetic baselayers that also provide warmth.
Flint outlines the key UPF characteristics in a handful of materials and then highlights which activities these materials best serve.
Material | UPF Benefits and Beyond | Best For |
|---|---|---|
| Paddle boarding, hiking, fishing because the fabric is lightweight and breathable even when wet and dries fast on water | |
| Climbing, scrambling, trail use because nylon offers strong abrasion-resistance, even in rugged conditions, while also providing prolonged sun protection | |
| Backcountry skiing, cold-weather hiking because merino shields from sun and snow glare and maintains performance in variable conditions | |
| Casual wear, yoga, light hiking because these blends provide soft, breathable comfort for low-intensity or short-duration sun exposure | |
Treated Cotton | Not inherently UV-protective, but UV-blocking properties can be added through fabric treatments, blended contents or dense weaves | Travel, lifestyle wear because cotton provides a comfortable everyday option for moderate sun exposure with added coverage |
UPF Clothing Features
Here are some of the other features that UPF clothing might have.
- Extended coverage: Some shirts have flip-up sun collars; others might have cuffs that are shaped to extend coverage over the back of the hands. In hats, look for broad brims and neck capes.
- Vents: Tight weaves, thick fabrics and extended coverage also work to heat things up inside, so look for plenty of ventilation options like overlapping panels or mesh behind zippers that let air circulate without exposing too much skin.
- A looser cut: Steer clear of stretchy garments that fit too tightly, because a garment that's stretched can become significantly less effective at blocking UV light. More loosely cut rigid fabrics also increase thermal comfort through air movement.
- Quick-drying fabrics: Wetness can cause a significant reduction in a fabric's UPF rating, so having a garment that dries quickly will get you back to your full UPF rating sooner. (Packing along dry UPF-rated clothing is another strategy.)
Sun Protection Beyond UPF Clothing
Ensuring you have UPF-rated clothing is important, but total UV protection requires a multifaceted approach:
- Clothing: Wear UV-protective clothing that covers a significant amount of your skin.
- Sunscreen: Liberally apply sunscreen with a high SPF rating to all exposed areas of skin. Reapply regularly—sunscreen loses performance as time passes.
- Sunglasses: Wear ones that offer 100% UV-ray protection.
- Shade: Seek shade whenever possible, and keep in mind that water, snow and reflective surfaces can increase your UV exposure.
- Exposure time: Monitor, and limit, the amount of time you expose yourself to UV radiation, especially during peak daylight hours—roughly from 9am to 3pm.
- Sun protection isn't just for sunny days: Filtered sun can still damage your skin, so protect yourself on cloudy days, too.
Taking these precautions will keep your skin healthier. Be smart about the sun, and it will be easier to soak up the fun when you're outdoors.
