Difference Between Clouds and Fog (with Table)

Whenever we look at the sky we see a white cotton-like thing scattered in the sky that looks marvelously beautiful and this beautiful thing is known as Cloud. Clouds are an important part of the water cycle. These clouds can form at different altitudes. They can be high as 20 km above the sea level and even low as the ground. So, the form of cloud which is low as the ground is known as Fogs. Fogs appear in the winter season and restrict our vision. 

Clouds vs Fog

The main difference between fog and clouds is that Clouds form when the water vapor (a gaseous form of water) turns into liquid and form on tiny particles like dust whereas fog is formed when the air near the ground cools enough to turn its water vapor into liquid water or ice.

Also, clouds can form at any altitude and are present in any climate whereas fog can only form at ground level and are present during cold climatic conditions only.

Comparison Table Between Clouds and Fog

Parameter of Comparison




Clouds are present at any altitude.

Fog is present at ground level only.


Clouds are significant because they contribute to the water cycle.

Fog is not so significant.


Throughout the year.

Winters only.



0.05g/m3 – 0.5g/m3

Occurrence of condensation

Condensation occurs high in the atmosphere.

Condensation occurs close to the ground.

Precipitation of Water back

Clouds precipitate water back in the form of rain.

Fog doesn’t precipitate water back. 

What are Clouds?

Clouds are a mass of ice crystals or water drops suspended in the atmosphere. They are an important part of the water cycle. They also contribute to Earth’s weather and climate. There are 10 types of clouds classified into 3 different levels:

  • High-Level Clouds: There are three high-level clouds:
  1. Cirrus(Ci): This type of clouds often appear like white patches in the sky. Cirrus is made up of ice crystals and they appear bright yellow or red before sunrise and after sunset.
  2. Cirrocumulus(Cc): This type of cloud is like a thin white patch or sheet layered in the sky without shading. They appear as small elements arranged randomly.
  3. Cirrostratus(Cs): This type of cloud is transparent and more like a white veil or a sheet of white butter paper. It is not opaque enough to block sun rays.
  • Mid-Level Clouds: There are three types of mid-level clouds:
  1. Altocumulus (Ac): They have a grey and white patch like or layered sheet-like appearance. Most of the small elements arranged in this type of cloud constitute a width of a little finger.
  2. Altostratus (As): They are somewhat greyish -bluish kind of sheets or layers that covers the sky totally or partially. They are translucent.
  3. Nimbostratus (Ns): These are dark grey colored cloud layer which gets diffused by falling rain or snow. They are opaque and don’t allow sunlight to pass through it. 
  • Low-Level Clouds: There are four types of low-level clouds:
  1. Cumulus (Cu): There are dense clouds with sharp outlines that get developed in the form of towers, buildings.
  2. Cumulonimbus (Cb): This is the thunderstorm cloud. It is huge, dense, and appears like a mountain. 
  3. Stratocumulus (Sc): These are like grey or whitish colored patch or sheet-like layered clouds that have a dark honeycomb-like appearance. 
  4. Stratus (St): These are grey clouds with a uniform and dense layer. They produce ice prisms, snow grains, etc.

Clouds are formed when water from the ground or any water body gets evaporated in the form of water vapor by trapping the heat and leaving the water behind them cooler. Then this water vapor forms on the dust particles present in the air forming water drops by the method of condensation and such water drop combine to form clouds.