Seasonal Depression?

[Alldara]

This is my first Winter with Louise, but I notice that on those cold days with
weak or no sun and she cannot sit on the sunporch, she mopes around and sleeps more than usual .

The do seem solar powered! Mine always sleep more on rainy or cloudy days.

Nobel's winter melancholy seems unrelated to how much sun is shining and goes on in November/December for a few weeks before we put up the Yule Tree. I'm not a big "Christmas" person. My motivation to put the tree up is Nobel and my wife, as we don't have guests due to COVID.