Not sure what you are seeing, but receptacles and switch boxes are subject to air pressures that either bring air into the room or exhaust air out. The pressures are either normal stack effect (SE) or the result of fans somewhere. If we look at just the SE during cold weather the direction is in at the lower areas and out at the upper. There are exceptions we won't get into here.
Now, the air inside those walls can be coming from your basement as the overall direction is up.
Does this reading repeat later on?
Is there any pattern to where you see this, high or low?
Bud
Now, the air inside those walls can be coming from your basement as the overall direction is up.
Does this reading repeat later on?
Is there any pattern to where you see this, high or low?
Bud
