Happy Met Gala Monday to those who celebrate — but if you’re going out during the daytime, you may want to rethink the “naked dress.”

While fashion fans all know the first Monday in May is when stars strut the red carpet at the Metropolitan Museum of Art’s Costume Institute Gala, the medical community knows it better as “Melanoma Monday,” marking the start of Skin Cancer Awareness Month.

And as summer is right around the corner with sunnier days ahead, it’s important to take a look at how our wardrobe choices can affect cancer risk.

Reducing the risk of skin cancer is essential, as more than 9,500 people are diagnosed daily and 1 in 5 adults will develop the disease by age 70.

What you wear, from your head to your toes, can either reduce or increase your cancer risk, according to Gloria Lin, a board-certified dermatologist at Schweiger Dermatology in New York City.

“Clothing can make a huge difference for sun protection because this is something that is more consistent and does not need to be reapplied,” she told The Post.

The best fabrics — and the worst

Though many gravitate toward linens and cotton in the warmer, sunnier months, these materials aren’t the best for sun protection. Instead, Lin said, we should reach for fabrics like polyester, nylon, merino wool, denim and corduroy.

And while crochet, lace and mesh are trendy for festivals and beach days, they also “allow for UV rays to penetrate through the larger holes in between the fabric fibers,” Lin noted.

Don’t be afraid to don your shiniest silks to your next summer soirée, as lustrous fabrics can potentially reflect radiation during outdoor events.

Shapes, silhouettes — and sneaky cancer threats

It should come as no surprise that the less skin you’ve got covered, the greater the risk of sun exposure and potential skin cancer.

“Clothing like crop tops, halter tops, backless tops or low-cut tops all have this issue because of the amount of extra skin that is exposed,” warned Lin. “If you are going to wear this style of clothing, then I recommend sunscreen use and reapplication.”

Looser-fitting clothes are actually better than tighter ones, she added.

“The tight clothing can stretch, then the fibers are pulled away from each other, and this allows more light to pass through.”

The darker the clothing, the better

It may be tempting to reach for your brightest whites once it’s no longer a fashion faux pas past Memorial Day — but Lin says darker or brighter colors like black, navy and red are the way to go.

“Even within a particular color, the more intense the hue, the better for protection,” she said. “While it may feel hot in the sun in darker colors, more of the UV is absorbed into the fabric and less hits the skin.”

Without additional UPF, though, sun rays can still penetrate the fabric, regardless of how thick or dark it is.

What’s the deal with UPF?

Sunscreen protect is measured in SPF — but clothing protection is measured in UPF (Ultraviolet Protection Factor).

The best options are those labeled with a UPF rating of 50+, which tests how much UV radiation can reach the skin through the fabric.

“Typically, UPF 50 blocks about 98% of the UV rays from the sun,” Lin said. “So 2% ends up penetrating, which drastically reduces the exposure.”

You don’t have to choose between fashion and function these days, as many UPF clothing options are considered fashionable.

“There are so many more UPF clothing options on the market with a lot more range and versatility that help make sun protection look cute and chic,” Lin explained. “At least at the beach or for casual outdoor activities.”

But while many items are treated with UV-absorbing or reflecting chemicals for extra security, these can wear off over time and multiple trips through the washer and dryer.

Lin recommends checking the label for how many washes the additional chemicals can last, and following the care instructions to preserve the longevity.

“Plus, all clothes do become more worn or faded over the lifetime, so when this happens, then their UV protection does decrease,” she added.

Don’t forget accessories

No outfit and day out under the sun is complete without the final touches like hats, sunglasses and even UV umbrellas.

Consider adding a sun hat to your ensemble for additional protection to the scalp, face, eyes, ears and neck, especially as Lin says skin cancer is more common on the head and neck.

“Find a wide-brimmed hat, at least 3 inches, to cover all these body areas,” she suggested. “Areas like the ears and back of the neck are often overlooked when sunscreen is applied.”

Wearing a light jacket, long-sleeve button-down shirt or shawl, or carrying a sun umbrella or parasol while you’re outdoors, also helps protect the skin and is a bonus if your final indoor destination has the AC blasting.

The number one preventive measure? Daily sun protection as UV exposure is cumulative over the lifetime, especially if you’re wearing items like crop tops, halter tops, backless or low-cut garments that increase exposure.