Let me correct myself. Moisture generally refer...

Let me correct myself. Moisture generally refers to the presence of water, often in trace amounts. There is practically no moisture in the atmosphere of mars, the atmosphere is considered "dry".

The clouds are not moisture, they are ice clouds.

The atmospheric pressure is too low on surface of the planet, thus there is a direct transition of ice -> gas without a liquid intermediate.

While there is considerable water in the Martian soil, I would not call the
soil "wet". Rather, the water is most likely in two forms--chemically bound
water (water of hydration, chemically bound to the minerals) and physically
bound water. The physically bound water, also known as "adsorbed" water,
consists of water molecules attached to the soil grains by van der Waals
forces. Typically, the bonds are stronger than in liquid water, and there
is no more than a single layer of water molecules covering the grains. If
the atmosphere were near saturation, the number of layers of water on the
grains would increase. If it got to be more than a few molecules thick,
then it would behave like liquid water and we would consider it to be liquid
water.