Arock layer that collects and stores
water is

An aquifier

Explanation:

An aquifer holds water. For example, picture the sinkholes of florida. They fill with so much water that it is where zephyrhills water comes from.

if the temperature drops and becomes cool

then the atmosphere can be freezing as the water vapor in the air is at maximum (100%) and can be severely cold

also can be snowing lightly as the moisture in the air will start to solidify

and btw this is not chemistry but