For years,domestic vehicles were switching on the AC compressor on a cold day when you switched on defrost mode. Really dumb, relative humidity for actual humidity goes way when temperatures decrease. Idiots were switching on the AC to get rid of this almost nothing humidity.
AC compressors are like a two cycle engine lubrication is mixed in with the refrigerant, cheapest way to do it, even in your home AC or refrigerator has a sump for lubrication, only refrigerant is pumped.
By running the AC compressor, pressures are much lower, circulating very little lubrication, not removing practically any moisture, the only thing you are doing is wearing out your compressor by switching it on at this low temperatures. At least the South Koreans and Japanese realize this, so they do not automatically switch on the compressor in defrost mode.
With the advent of R-134a, AC repair has become very expensive, another lie from our government claiming R-12 was depleted the ozone layer. Real cause of the antarctic ozone depletion was lack of sunshine in the south pole during their winter time. Need sunlight to form ozone.
R-134a is using a women's facial cream for lubrication, with moisture forms an acid that eats away your AC system. R-12 never had this problem.