If you can get to the back of the unit, check and see whether it has one or more small vent holes. If so, gently probe them to see if there is dirt or some other blockage there that may be preventing the atmosphere inside the gauge from equalizing humidity etc. with the outside. Not all devices have these vents, but if they do and they become blocked, they can trap a slightly higher level of moisture inside than the condensing level outside - especially when going from a warm garage to cooler outside morning air.
Moisture, let alone cool air, is not usually an issue here in the Mojave...
