Regardless of whether it's snow, some other light (or even dark) expanse, large-scale uniform color will confound the even the newest exposure sensors. The trick is to make your exposure for the contrast in the composition, and bracket your shots.

Your equipment
Before you go diving in and snapping pictures of the frost and ice clinging to the bare limbs of some ancient arboreal growth, or you try to shoot the latest incarnation of Frosty in the front yard, you need to know a thing or two about winter photography. First and foremost, you must be aware of the battery in your camera. Batteries hate cold, and will lose their charge dramatically faster and longer they're exposed to the cold.

If you're on a location shoot, keep your camera, or its battery at the very least, inside your coat until you're ready to start shooting. Extra batteries, also kept inside that nice warm coat, are a mandatory for a winter location shoot.

The second thing to keep in mind is the effect of the environment on your camera. Your camera needs to adjust to the cold before it can be used. A warm camera suddenly exposed to frigid temperatures will fog up from the moisture of the air in and around it. Give the camera a few minutes, the few minutes it will take you to install that warm battery, to let it temperature adjust.

When you return from your shoot, the converse is true as well. A cold camera brought into a warm environment will fog again as warm moisture condenses on, and in, the unit. Let the camera come to room temperature for a couple of hours to ensure all the moisture has evaporated before storing in it.

The typical dry conditions of winter can also wreak havoc on film, if that's what you're shooting. Rapid advancement of the film can actually generate static electricity inside the camera, damaging the film and causing streaks as it's advanced.

And finally, that cold, dry environment can also affect the shutter, slowing down its response. This is one more justification for bracketing your shots.