When temperatures soar, it’s essential to choose the right clothing to stay cool and avoid heat-related issues. Dressing for hot weather can be a challenge, but with the right approach — taking into account fabrics, colors and more — you can stay comfortable all day long.
Whether you’re heading to the beach, running errands or going for a hike, here’s how to dress appropriately to safely beat the heat.
Stick With Natural Fabrics Like Cotton and Linen
The best fabrics to stay cool when it’s hot outside are cotton and linen. Cotton is a natural fiber known for its breathability and ability to absorb moisture, which helps keep your skin cool and dry. Its lightweight and soft texture makes it comfortable to wear and allows air to circulate freely, enhancing its cooling effect.
Linen is also breathable and has excellent moisture-wicking properties. It’s also commonly used in flowy, loose-fitting garments that won’t keep sweat trapped on your skin. “If the sweat’s just sitting on you, then it’s not evaporating, and therefore it’s never actually leaving the surface of your body and it’s harder for your body to stay cool,” Kimberly McMahon of the National Weather Service’s Public Weather Services Program told TIME.1
While synthetic sweat-wicking or moisture-wicking fabrics are commonly recommended, these technical fabrics are often made from polyester, which poses health and environmental risks. Further, research suggests natural fabrics work just as well to keep you cool. One review, published in Sports Medicine, stated:2
“Clothing construction, fit, and fabric are all critical influences on the amount of sweat absorbed from the skin and transported throughout the clothing. The majority of the research analyzing advertised synthetic fabrics has shown no difference in thermoregulation or clothing comfort while exercising in those fabrics in the heat compared to natural fabrics.”
Other studies have also compared cotton with synthetic fabrics made from polyester or nylon, finding cotton works well for exercising in the heat. Researchers with Deakin University in Geelong, Australia wrote in Sports Medicine Open that some “studies have observed no comfort or thermoregulatory benefit from wearing polyester during exercise when compared to cotton.”3
Further, other research “identified no significant reductions in core temperature, skin temperature, sweat rate, sweat loss or skin/clothing wettedness when comparing nylon and cotton sports clothing despite using similar testing protocols.”4 They further noted:5
“Cotton is a natural fiber with better moisture absorption capabilities than most synthetic fibers … thermal sensation was significantly improved when wearing a cotton t-shirt during exercise in hot and dry conditions compared to an upper body compression garment composed of nylon.
Indeed, some studies have reported significant reductions in core temperature, skin temperature, sweat loss, and heart rate when wearing cotton clothing during exercise compared to synthetic fabrics.”
Problems With Polyester and Other Synthetic Fabrics
Technical fabrics used in athleisure are popular for their moisture-wicking, quick-drying claims. But they may not offer the best option, in part due to a lack of moisture-absorbing qualities. According to the Sports Medicine Open study:6
“Polyester is the most commonly used synthetic material in sports apparel due to its dimensional stability, smooth feel, and low cost. However, its low moisture absorption may be a limitation during situations of immense sweating as the increased moisture on the skin’s surface may lead to sensations of skin wettedness and discomfort.”
Further, synthetic materials often contain problematic chemicals. Polyester and spandex, for example, contain high levels of estrogen-mimicking bisphenol A (BPA).7 Synthetic fabrics are also likely to shed copious amounts of microscopic plastic fibers each time they’re washed. In a comparison of acrylic, polyester and a polyester-cotton blend, acrylic was the worst, shedding microfibers up to four times faster than the polyester-cotton blend.8
Due to their tiny size, these microfibers9 flow straight through the wastewater treatment plant without being caught, allowing them to enter rivers, lakes and oceans. Microfibers are ingested by aquatic organisms, from small plankton to larger fish and marine mammals, which can cause blockages in the digestive system and potential exposure to harmful chemicals attached to the fibers, which can affect growth, reproduction and survival rates.
The microfibers also move up the food chain, reaching people who consume seafood and other contaminated foods. And because microfibers are made from durable synthetic materials like polyester, nylon and acrylic, they do not biodegrade easily. This means they can persist in the environment for decades or longer, continually impacting ecosystems and human health.
Long Sleeves and Pants Are Better Than Sunscreen
While you may be tempted to wear as little clothing as possible when it’s hot outside, there are times when long sleeves and pants make sense, even when temperatures are high. After you’ve gotten your daily dose of sun exposure, if you plan to spend more time outdoors, wearing long sleeves and pants can help you avoid sunburn and are a better option than toxic sunscreen.
The health risks of sun exposure come from getting burned, i.e., overexposure. But sunscreens typically contain toxic chemicals like oxybenzone, a known endocrine disruptor linked to reduced sperm count10 in men and endometriosis11 in women.
Sunscreen chemicals are absorbed systemically into your bloodstream after just one application, posing significant health risks. “Studies in the literature have raised questions about the potential for oxybenzone and homosalate [another sunscreen chemical] to affect endocrine activity,” researchers wrote in JAMA.12
“In addition, multiple active ingredients lack nonclinical safety assessment data, including systemic carcinogenicity, developmental, and reproductive studies to determine the clinical significance of systemic exposure of sunscreen active ingredients,” they continued.13
In addition to the risks posed by harmful chemicals, many sunscreens aren’t as effective as claimed. As a result, you may end up getting sunburned anyway. Covering your skin with long sleeves and pants made from natural fabrics is a safe and effective alternative to avoid overexposure to the sun.
Remember, daily sun exposure on your bare skin offers multiple health benefits; it’s only after you’ve had enough exposure for the day that you should cover up.
Dark Colors Protect Against Sun Better Than White
When choosing clothing to protect against excessive sun exposure, dark clothes work better than light. However, if sun exposure isn’t a factor, dark colors may end up making you hotter. Researchers from the National Institute for Environmental Studies in Japan investigated how the color of polo shirts affects their surface temperatures in sunny outdoor conditions.14
They found that dark colors like black and dark green can get more than 15 degrees C (59 degrees F) hotter than white shirts on sunny days. This temperature difference is most noticeable when the sun is very strong.
They discovered that about 24% of the temperature difference is due to how much solar radiation each shirt color absorbs. When considering how the shirts let through solar radiation, they found the absorption difference explains 34% of the temperature difference.
They also looked at the brightness and reflectivity of the colors. It turned out that red and green shirts had different surface temperatures because of how much visible and near-infrared (NIR) light they reflected, and NIR reflection played a big role in how hot the shirt got.
However, there is some controversy over whether wearing dark colors actually makes you hotter. The Bedouins, for instance, are a group of people who traditionally live in desert regions. They often wear black robes, which may seem counterintuitive in hot desert climates. However, while dark fabrics absorb more heat from the sun, the loose-fitting nature of the robes allows for air circulation, helping to dissipate heat before it reaches the skin.
Researchers with Tel Aviv University in Israel even investigated whether wearing black robes helps the Bedouins stay cool in the desert heat, noting:15
“We report here that the amount of heat gained by a Bedouin exposed to the hot desert is the same whether he wears a black or a white robe. The additional heat absorbed by the black robe was lost before it reached the skin.”
Margaret Frey, a professor of fiber science and apparel design at Cornell University, told TIME, “We can look for inspiration from traditional dress from very warm climates. In a lot of them, they are wearing things that actually cover most of the body but are not tight-fitting.”16
Choose Loose Clothing Over Tight-Fitting Options — and the Right Accessories
As mentioned, when it’s hot outside it’s typically better to wear loose-fitting clothing rather than fitted options. Loose clothing allows air to circulate more freely around your body. This helps sweat evaporate more efficiently, which cools you down. With more space between your skin and the fabric, loose clothing helps to dissipate body heat, whereas tight clothing can trap heat close to your body, making you feel hotter.
Loose clothing is also less likely to cling to your skin, reducing the accumulation of sweat. This helps keep your skin dry and prevents discomfort and irritation. Accessories are also useful to stay cool. Wide-brimmed hats provide excellent shade for your face, neck and shoulders, reducing direct sun exposure after you’ve had your daily dose. Choose hats made from breathable natural materials, such as cotton or straw.
You can also wet a lightweight scarf or bandana made from cotton or linen and wrap it around your neck for a cooling effect. Another important “accessory” is a glass water bottle filled with pure water. Carrying a reusable glass water bottle and sipping water throughout the day can help maintain your hydration levels and keep you cool in hot weather.17
