As the temperature decreases the molecules lose some of their energy, and compress onto particles in the atmosphere, shaping clouds.
Water molecules are stored in the atmosphere in all three states of matter. Water vapor in the atmosphere is commonly referred to as humidity. If liquid and solid forms of water can overcome atmospheric updrafts they can fall to the Earth's surface as precipitation. The formation of ice crystals and water droplets occurs when the atmosphere is cooled to a temperature that causes condensation or deposition. Four processes that can trigger such atmospheric cooling are oro-graphic uplift; convectional uplift; air mass convergence; and energy loss.  Precipitation can be defined as any aqueous deposit, in liquid or solid form, that develops in a saturated atmospheric environment and generally falls from clouds. A number of different precipitation types have been classified by meteorologists including rain, freezing rain, snow, ice pellets, snow pellets, and hail. Fog represents the saturation of air near the ground surface. Classification of fog types is accomplished by the identification of the mechanism that caused the air to become saturated.  The distribution of precipitation on the Earth's surface is generally controlled by the absence or presence of mechanisms that lift air masses to cause saturation. It is also controlled by the amount of water vapor held in the air, which is a function of air temperature. A figure is presented that illustrates global precipitation patterns.
Clouds and Their Formation:
A cloud can be defined as a visible mass of condensed droplets, frozen crystals suspended in the atmosphere above the surface of the Earth. More importantly, these clouds can also occur as masses of material in interstellar space, where they are called interstellar clouds and nebulae.  On Earth the condensing substance is typically water vapor, which forms small droplets or ice crystals, typically 0.01 mm in diameter.  When surrounded by billions of other droplets or crystals they become visible as clouds. Dense deep clouds exhibit a high reflectance (70% to 95%) throughout the visible range of wavelengths: they thus appear white, at least from the top. Cloud droplets tend to scatter light efficiently, so that the intensity of the solar radiation decreases with depth into the cloud, hence the gray or even sometimes dark appearance of the clouds at their base.  Thin clouds may appear to have acquired the color of their environment or background, and clouds illuminated by non-white light, such as during sunrise or sunset, may be colored accordingly. In the near-infrared range, clouds would appear darker because the water that constitutes the cloud droplets strongly absorbs solar radiation at those wavelengths. 
Types of Clouds:
Although there are many types of clouds with respect to their different characteristics, clouds are mainly divided into three major classifications. These are as under,
Cirrus Clouds: The name originates from the Latin word meaning "curl of hair". These feathery clouds form very high up in the sky (at altitudes between 5 km and 14 km) where it is very cold.  They are therefore made up of tiny ice crystals rather than water droplets. Cirrus clouds occur in warm air which is being slowly lifted over a large area by an approaching cold front, and they