As long as moisture is not condensing and running into or dripping on the live circuits, you have nothing to worry to about.
Note moisture typically collects when there is a fairly extreme change in temperature - such as might happen when the computer has been running and is warm, then turned off and allowed to cool in a cold room such as yours. Or when cold, powered on and allowed to warm up. So you need to ensure the case interior has plenty of dry air ventilation to ensure moisture does not collect in the first place.
While there is such a thing as too cold when it comes to electronics, your (indoor) temps are not near cold enough for those worries.
There are many who envy your cool CPU temps!
And yeah, when I think of...