It's easy to shove your SPF into the bottom drawer along with your bikini and sandals, but it's important to keep your summertime sunscreen regimen intact. Sure, winter means fewer daylight hours and more time spent indoors, but UVB rays can still damage darker skin year-round, especially at high altitudes and on reflective surfaces such as snow or ice.

Replenish your stock of broad-spectrum sunscreen (one that protects against both UVA and UVB rays) with SPF 30 or higher and active ingredients like zinc oxide, avobenzone or mexoryl, like Aveeno Protect + Hydrate Lotion Sunscreen with Broad Spectrum SPF 30, $9.99.

The holiday season may quite possibly be the worst time to jumpstart any sort of diet. Luckily, keeping your skin hydrated simply means reminding yourself of the basics. Charles suggests upping your water intake to at least eight glasses of water a day to help keep thirsty skin hydrated. If leafy greens, avocados, almonds and salmon are playing second fiddle to Turducken and pie, use your extra water intake to wash down vitamin E and omega-3 fish oil capsules to moisturize skin from the inside out.

Related: 9 Best (and Worst) Foods for Healthy Skin.

The visibility of ashy and scaly skin makes it tempting to double up on exfoliation to keep flakes and dryness at bay, but going harder on the scrubbing front can backfire in the long run by causing even more dryness. The same goes for your harsh acne and anti-aging products. "Strong retinoid creams must be used more sparingly in the harsh winter months," says Charles.

If your skin still feels dry, check other parts of your skin care routine. Try swapping your foaming or exfoliating cleanser for a more moisturizing, creamy cleanser, or swap harsh astringents, toners or makeup removers for multitasking micellar waters that clean the skin with fine oils suspended in water. If your skin is feeling particularly raw, try the super gentle Avene Micellar Lotion, $20 or Darphin Ahazar Cleansing Micellar Water, $40, which contains moisturizing neroli oil.

To keep the rest of your skin hydrated, swap scented (read: irritating) body washes for gentle, fragrance-free soaps like Dove Sensitive Skin Unscented Beauty Bar, $3.47, or Aveeno Skin Relief Body Wash, $6.99. "Laundry detergent for sensitive skin such as ALL or Arm & Hammer for Sensitive Skin can also be helpful," Charles adds.

We naturally gravitate toward heat in the winter months, but too much can do a number on parched winter skin. Do damage control by avoiding long hot showers and baths -- even though you're soaking your skin in water, the high temperature causes moisture to be drawn back out of your skin. Learn to embrace tepid temperatures and always gently pat your skin dry and slather on a fragrance-free lotion while the skin is still damp to seal in all the room-temperature moisture.

Your skin is also at risk of dehydration when you're out of the tub. If you can't bear to turn down the thermostat, sleep with a humidifier in the bedroom to return some moisture to the air.

Thanks to food comas and fewer hours of daylight, it's easy to log more z's in the wintertime. Take advantage of the extra shuteye by trying a moisturizing sleep mask. According to Charles, since your skin is in renewal mode, a moisturizing mask can help lock in moisture, making your skin better equipped to fight harsh winds and cold, drying temperatures. Plus, multitasking while you sleep makes life much easier.

When choosing your overnight mask, look for moisturizing ingredients like mushroom and ginkgo extract, hyaluronic acid, aloe and natural oils like avocado and apricot kernel, which will not only give fight off flakes and that tight feeling, but give you a good glow. Origins Drink Up Intensive Overnight Mask, $24, is a good place to start. Skip the extra-rich night cream and indulge in your nighttime mask three to five times a week.