While not always true, many runs in the dark are also during the colder months. When it is true, Nathan has a couple of clever solutions for warmth and safety, with the Domelight skullcap and the SpeedShift gloves.
Both feature USB charging for their LED lights, the Domelight with white in the front, boasting 2400 foot visibility, and red in the back, and the SpeedShift with red on each glove's back. The bit of reflectivity and the row of lights, combine with the movement from your hands while running, to make them even more noticeable. Both also feature fleecy interiors to trap warmth and wick perspiration, and DWR water resistant treatment on the outside to shed moisture from the atmosphere.