As the seasons change, so does your skin -- and doctors say now is the time to prepare your skin for the winter weather ahead.

“Wintertime in particular across the country tends to be a time of drier air on the outside, as well as more drier air on the inside because we’re using a lot of radiant heat that really dries out our skin,” said Dr. Anne Chapas of Union Square Dermatology in New York City.

Chapas said that moisturizing isn’t just part of a beauty regimen, as keeping your skin moisturized also protects your body from things getting in.

“Skin is our biggest organ and it’s our first line of defense; it’s actually our largest immune system,” she said.

When skin is moisturized, it has a stronger barrier to resist damage. When it’s dry, it actually makes cracks and fissures that allow germs to enter the skin and create irritations and eczema. Skin care isn’t just about skin being dry or moisturized, but rather about the skin being protected and acting as a barrier.

Additionally, there are other ways to keep the moisture in and germs out. Chapas suggests taking shorter showers in the winter, then applying moisturizer as soon as you get out.

According to Chapas, it’s important to moisturize on a regular basis because as we get older, so does our skin and it gets more dry.  “Our circulation also decreases, which can also affect our skin,” she said.

And as for sunscreen, there is no season you can go without it.

“We need sunscreen all year round because the sun is always damaging our skin.  Also, a lot of us are engaging in higher-elevation sports like skiing where we’re actually getting more sun damage because we’re at that higher elevation. So it’s important to wear an SPF 30 on our face, year-round,” Chapas said.

Chapas suggested leaving your skin care products next to your toothbrush, so once you take care of your teeth, you’ll remember to take care of your skin.

Dr. Manny Alvarez serves as Fox News Channel's senior managing health editor. He also serves as chairman of the department of obstetrics/gynecology and reproductive science at Hackensack University Medical Center in New Jersey. Click here for more information on Dr. Manny's work with Hackensack University Medical Center. Visit AskDrManny.com for more.