Dress in loose layers and warm up indoors before cold-weather runs
Added
As mornings get colder, warm up first (walk or march in place), then head out in several loose layers with a hat and gloves, and add a waterproof jacket if it's wet. Check the forecast and move the workout indoors if it's too windy, icy or wet, and tell someone your route.
The result
Result: National Institute on Aging: layers of loose clothing trap warm air between them; wear nonskid, rubber-soled shoes on snow or ice, know the signs of hypothermia, and carry a fully charged phone.
Note: Not medical advice. Talk to your doctor before changing your training, diet, or supplements.
Source
National Institute on Aging: 5 Tips for Exercising Safely in Cold Weather (opens the original source in a new tab). Check it for the latest numbers before you act.