Factors affecting climate


Latitude or Distance from the Equator

The places near the equator are warmer than the places which are far away from it.

This is because the rays of the sun fall vertical on the equator and slanting in the temperate and polar regions.

Therefore, lower the latitude higher is the temperature and vice versa.

 

Altitude or the Height from the mean sea level

Mountains are cooler than the plains.

The temperature decreases with the height of a place.

For a vertical rise of 165 metres there is an average decrease in temperature at the rate of 1°C.

Thus the temperature decreases with increase in height.

 

The Distance from the Sea

The water is a bad conductor of heat i.e. it takes longer time to heat and longer time to cool.

Due to this moderating effect of the sea, places near the coast have low range of temperature and high humidity.

The places in the interior of the continent do not experience moderating effect of the sea. These places have extreme temperatures.

The places far from the sea have higher range of diurnal (daily) and annual temperatures.

Mumbai has relatively lower temperature and higher rainfall than Nagpur, although both are almost situated on the same latitude.

 

Nature of the Prevailing Winds

The on-shore winds bring the moisture from the sea and cause rainfall on the area through which they pass.

The off-shore winds coming from the land are dry and help in evaporation.

In India, the on-shore summer monsoon winds bring rains while off-shore winter monsoon winds are generally dry.

 

Cloud Cover

In areas generally of cloudless sky as in deserts, temperature even under shade is very high because of the hot day time sunshine.

At night this heat radiates back from the ground very rapidly.

It results in a large diurnal range in temperature.

On the other hand under cloudy sky and heavy rainfall at Thiruvananthapuram the range of temperature is very small.

 

Ocean Currents

Ocean waters move from one place to another partly as an attempt to equalize temperature and density of water.

Ocean currents are large movements of water usually from a place of warm temperature to one of cooler temperature or vice-versa.

The warm ocean currents raise the temperature of the coast and sometimes bring rainfall, while the cold currents lower the temperature and create fog near the coast.

The on-shore winds passing over a warm current carry warm air to the interior and raise the temperature of the inland areas.

Similarly, the winds blowing over cold current carry cold air to the interior and create fog and mist.

 

Direction of Mountain Chains

The mountain chains act as natural barrier for the wind.

The on-shore moisture laden winds are forced to rise after striking against the mountain; and give heavy rainfall on the windward side.

These winds descending on the leeward side cause very low rainfall.

The great Himalayas check the moisture laden monsoon winds from crossing over to Tibet.

This mountain chain also checks biting polar cold winds from entering into India.

This is the reason for which northern plains of India get rains while Tibet remains a perpetual rain shadow area with lesser amount of rainfall.

 

Slope and the Aspect

The concentration of heat being more on the gentler slope raises the temperature of air above them.

Its lesser concentration along steeper slopes lowers the temperature.

At the same time, mountain slopes facing the sun are warmer than the slopes which are away from the sun’s rays.

The southern slopes of Himalaya are warmer than the northern slopes.

 

The Nature of the Soil and Vegetation Cover

The nature of soil depends upon its texture, structure and composition.

These, qualities vary from soil to soil.

Stony or sandy soils are good conductor of heat while black clay soils absorb the heat of the sun’s rays quickly.

The bare surface reradiates the heat easily.

The deserts are hot in the day and cold in the night.

The forest areas have lower range of temperature throughout the year in contrast to non-forested areas.