Even though we've been known to use it as one, cold weather is not a good excuse to not go outside to walk or run. If you take the right precautions, and check the weather before you venture out, you should be able to continue your exercise regimen all year long.
It's definitely harder to get motivated when there is a bitter chill in the air, but the rewards of exercising should convince us that it's all worth it. Wearing layers to keep warm and covering up exposed skin will help keep you safe. And if the sun is shining even though it's cold, you can delude your happy self into thinking it's warmer than it is.
Here is a list of websites with good information to help you maintain your workouts in the cold. If you can only walk or run outdoors when it's dark, Be SURE to take along a flashlight or wear a reflective vest so that drivers can see you.
And for further reading, here's an article by The New York Times that says even though most Americans know they should exercise -- we do not. It's a puzzlement, for sure, and one I wish I could solve for myself. Read on: Why we don't exercise