Getting out and about in the winter can be just as enjoyable as doing so in the spring and summer, if you just remember to get prepared for everything the weather will throw at you. Most sports companies make a range of winter running gear these days, so there really is no excuse to stay in and lose your fitness.
One of the things that people worry about is losing their grip on the road or trail, and this is why it makes sense to have several pairs of running shoes. At the very least, it is wise to have a pair of shoes for the warm weather, and a separate pair for trail running through mud during the wet weather. If it snows where you live during the winter, one easy solution is to buy a pair of Yaktrax. These are metal and rubber attachments that you fix to the bottoms of your shoes, which prevent you from slipping on snow and even on sheet ice.
The next thing, once you know you are on a firm footing, is whether you will be warm enough. The important thing is to layer your clothing on your torso. It is usually good enough to wear a base or compression layer, with your regular running shirt over the top. In very cold weather you might also opt for a running jacket, and if you plan on running in the rain, then a waterproof outer garment is best. Make sure your layers are made from moisture wicking fabrics to transport sweat away from your skin.
What you wear on your legs is purely down to personal preference. For the majority of people, their regular shorts are fine, because the legs warm up quickly during exercise as they do most of the hard work. If you are running through snow, however, you might prefer to wear some jogging pants or tracksters. Aim for something breathable and light in weight though, so you do not feel like you are trudging along; often, heavy cotton pants can make jogging pretty slow, hard work if you are churning out high mileage.
Finally, you might need a couple of extra accessories that are definitely not needed during summer a pair of gloves and a nice warm beanie to keep your hands and head cosy and protected from the biting wind.