The walls of the house, if they have picked up moisture or have not dried since the construction of the house (which happens very often), will never dry themselves. For drying in our climate there are no necessary conditions of temperature and air humidity.
Previously, we found out that it is internal humidity that poses a threat. In the warm season, when the sun warms the house from the outside, humid air easily leaves the house and the walls do not absorb even more moisture. A small layer of plaster up to 10 mm even dries. This creates the illusion of dry walls. Naturally, the thickness of the wall remains completely damp and mold simply does not come to the surface.
With the onset of rains, when air humidity increases greatly, moist air from the house can no longer easily escape into the street. Left trapped in the house, humid air leads to wet plaster and activates the growth of mold on the walls and ceiling.
After drying the walls, this process stops due to the creation of a moisture-resistant barrier between the street and the house.