Winter has officially begun. That means the sun is sitting lower in the southern sky and most of us are spending less time outdoors because it is just too darn cold. When we do venture out, we're usually bundled to our ears.

But that's no reason to forgo sunscreen during winter months, said Dr. Quenby Erickson, a dermatologist and skin cancer surgeon at St. Louis University Hospital.

"People forget and think they don't need to wear it because they're not outside very long," she said. "They'll wear it every single day in the summer but not in the winter."

Slathering sunscreen on exposed body parts such as the face is especially important when participating in outdoor activities, Erickson said. And even when you're not.

"God forbid you're stuck outside unprepared," she said. "If you get a flat tire or are waiting in a parking lot for someone to come, you could get a sunburn."

Erickson, the Skin Cancer Foundation and the American Academy of Dermatology offered these tips and facts about the sun and our skin in winter:

• The sun produces two types of ultraviolet rays: UVA and UVB.

• UVA rays, which account for up to 95 percent of UV rays that reach the Earth's surface, penetrate deeper into skin, cause wrinkles and have been associated with melanoma, the most deadly type of skin cancer.

• UVA rays are almost equally intense during all daylight hours throughout the year; they can penetrate clouds and glass.

• Runners, cyclists, hikers, ice skaters and other athletes who workout outdoors year-round lose some sun protection as trees lose leaves.

• Skiers are exposed to an extra 8 percent to 10 percent of UV radiation for every 1,000 feet of altitude. "On top of that, 80 percent of those rays are reflected from the snow so it's a double-whammy," Erickson said.

• Wear wraparound sunglasses that provide UV protection to skin near the eyes and fight damaging glare, especially while skiing.

• Protect your lips with a balm that has sunblock. Sun exposure can decrease the immune system and bring out cold sores, from herpes 1 or 2.

• Use thicker sunblocks or zinc oxide, which also help prevent windburn.

• Wear a balaclava face mask. "Those are great," Erickson said. "There's nothing better than clothing to protect skin. It's not a mystery why most skin cancer is on the face ... because it's exposed all year long."

• Hot water removes natural skin oils more quickly; warm water is best for bathing.

• Deodorant bars, strong fragrances in soaps, and products with alcohol can strip natural oils from the skin. Look for a mild, fragrance-free soap or cleanser that moisturizes.

• Keep showers and baths between five and 10 minutes to add moisture to the skin. More time will leave your skin dryer than before you started.

• Apply an ointment or cream while the skin is still moist after bathing, usually within three minutes.

• Use a humidifier indoors to put moisture back into winter air.