In some places across the US, snow has fallen and temps are below the 30s. If you're still gung-ho about running outside, staying warm is a big concern. So before you head out the door, after you're all dressed, warm up inside for a few minutes. Don't do anything that will get you sweaty since that moisture will make you cold once you're outside. Just get your body temp to rise a little. Do some push-ups, jumping jacks, jog around your living room, or charge up and down the stairs. If you need some other ideas, check out this dynamic warmup that includes high-knee marching and heel walking. If you head outside and you're a little warm to begin with, your body will remain warm once it hits the cold air. Not only will you feel more like running, but warm muscles are less likely to tear.