I am in the minority here.
I am in massachusetts. My shop was in an unheated barn. Most of my games passed thru there.
Six million dollar man stayed there, backglass and all for about 10 years.
6$ million dollar man survived fine.
Some other games with or without triple thick had backglasses peel.
I have not noticed any planking on the games there.

My game room is at a camp in maine. Also unheated most of the time. Games regularly see temps below freezing. I remove the backglasses in the winter and store them in my house now.
When they were in the barn they saw temps below zero.

I keep games much longer than other pinheads. It is not uncommon for me to own a game 5 to 10 years. If there were issues with the cold i would see them. YMMV

To sum all this up, i think you will be fine in washington.