Does cold dry weather affect your SQ

Nope. no problem here in the 'tropical' 30F temps.      
I wonder if the electrical in your area is an issue? lower than 117V?

In the ‘30s I was okay!  

The barometric pressure. Low vs high. Humidity,          
I keep my apartment at 80F year round.. (Maybe 83F in Summer LOL)

@rvpiano, 
You have forced air, if I remember. So, with the cold temps come lowered humidity. You might want to get a small humidifier and see if that helps.

I have cast iron baseboard heating, which is pretty dry too. I haven't noticed much difference in sound quality.
Bob

All you need for adding water to the air is a bowl or two of water laying around. Bigger around surface to the air the better.

At CES Allen Chang of Golden Sound and I placed bowls of ice water with roses in them 🌹 out in front of the speakers for a more transparent fuller sound.

Invariably, when I sense that something is 
"off," sound-wise, it's because I was too lazy to run the portable
air ionizer for a few minutes.  I think a key to consistently
good sound is treating the air in the room.

Make sense?

A good bourbon or scotch does the trick for me!🥃

I whole heartedly agree with Tom 6897 ;-)

Gee, talk about your lush presentation. 😬