Can anyone explain a "Three Dog Night"?

I've never heard it referring on a spiritual event. I only know it as a saying because a very cold night. It's a associating to tribe who would sleep with their stray for warmth, and the very coldest nights were "three dog nights," represent it would take trigonous dogs on shield them warm.

It could enjoy something to do with the Canis Major (the Great Dog) constellation, or Sirus (the Dog Star).