We've all been nagged about staying warm in the winter by a concerned elder: "You don't want to catch cold!" But that's absurd; everyone these days knows colds are only caused by viruses, right? Well, it's complicated.

It's not necessarily the cold itself that gets you sick; it's all the different aspects of winter weather as a whole (dryness, lack of sunlight, etc.) that combine to make the perfect storm of prime cold conditions. However, that doesn't mean a drop temperature doesn't contribute at all. Watch the full video from ASAP Science above to found out how, and stay bundled up out there—winter's only just begun. [ASAP Science]