Condensation or frost on cedar wall shingles on the shady side of the house, early in the morning on clear winter days, bothers many homeowners. They imagine that somehow vast quantities of water are escaping from the house.
In fact, what is happening is that the surrounding air is warming up faster than the cedar wall and so, for a short period of time, the wall is colder than the surrounding winter air. (Of course this only happens when your house is well insulated and the inside heat is not warming up the shingles.)
When humidity conditions are close to saturation, the outdoor air deposits water on the cedar the same way your indoor air frosts up a cold window.
As soon as the temperature stabilizes between the siding and the air, the frost should go away.
There is nothing to worry about here.