Factors Affecting Indian Climate

India is home to an extraordinary variety of climatic regions, ranging from tropical in the south to temperate and alpine in the Himalayan north, where elevated regions receive sustained winter snowfall. India’s climate is strongly influenced by the Oceans, Himalayas and the Thar Desert. The Himalayas act as a barrier to the frigid katabatic winds flowing down from Central Asia keeping the bulk of the Indian subcontinent warmer than most locations at similar latitudes.

The climate of India may be broadly described as tropical monsoon type. India’s climate is affected by two seasonal winds viz. the north-east monsoon and the south-west monsoon.

• The north-east monsoon commonly known as winter monsoon blows from land to sea whereas south-west monsoon known as summer monsoon blows from sea to land after crossing the Indian Ocean, the Arabian Sea and the Bay of Bengal.
• The south-west monsoon brings most of the rainfall during the year in the country.

As such, land areas in the north of the country have a continental climate with severe summer conditions that alternates with cold winters when temperatures plunge to freezing point. In contrast are the coastal regions of the country, where the warmth is unvarying and the rains are frequent. India, not only its physiographic divisions are diverse but also far more contrasting in nature. Each one of these factors (Size, Shape, location extent etc.,) has an impact on climatic conditions of India, be it temperatures, atmospheric pressure, wind system or precipitation.

Factors influencing the Indian climate

Location and Latitudinal Extent

• The Tropic of Cancer passes through the middle of the country. The  southern  parts  being  closer  to  the  Equator,  experience  high temperatures  throughout  the    The  northern  parts  on  the  other  hand  lie  in  the  warm temperate  zone.  Hence they experience low temperatures particularly, in winter.
• For example, Bangalore would be hotter than Faridabad. Broadly speaking parts lying south of the Tropic of Cancer receive more solar heat than those lying north of it.

Distance from the Sea

• Southern or  peninsular  India  is  surrounded  by  the  Arabian  Sea,  the  Indian  Ocean  and  the  Bay of Bengal, hence the climate of coastal regions of India is equable or maritime.
• Contrary to this, the climates of the regions located in the interior of the country are cut off from the oceanic influence. As a result, they have an extreme or continental type of climate.

Altitude

• The atmosphere becomes less dense and temperature also decreases with the height. For example, the cities located on the hills are cooler like Shimla whereas the cities lying in the plains will have hot climate like Ludhiana.

Mountain Ranges

• These ranges protect India from the bitterly cold and dry winds of Central Asia during winter. Further more, they act as an effective physical barrier for the rain bearing southwest monsoons winds to cross the northern frontiers of India.
• On the other hand, they check rain bearing South-West Monsoon winds and compel them to shed their moisture in India.
• Similarly, Western Ghats force rain bearing winds to cause heavy rain fall on the Western slopes of the Western Ghats.

Direction of Surface Winds

• The wind system also affects the Indian climate. This system consists of monsoon winds, land and sea breeze, and local winds. In winter the winds blow from land to sea so they are cold and dry.
• On the other hand, in summer wind blow from sea to land bringing the moisture along with them from the sea and they cause wide spread rain in most part of the country.

Upper air Currents

Besides surface winds, there are strong air currents called Jet streams which also influence the climate of India. These jet streams are a narrow belt of fast blowing winds located generally at 12,000 metre height above the sea level. They bring western cyclonic disturbances along with them. These cyclonic winds originate near the Mediterranean Sea and move eastwards. On their way, they collect moisture from Persian Gulf and shed it in the North western part of India during winter seasons. These Jet streams shift northwards during summer season and blow in Central Asia. Thus helps in the onset of monsoons.

Physiography

The physical features influence the air temperature, atmospheric pressure, direction of winds and  the  amount  of rainfall  in different  parts of  the  country.

El-Nino  & La Nina

• Weather conditions in India are also influenced by El-Nino which causes wide spread floods and droughts in tropical regions of the world. This warming of tropical Pacific waters affects the global pattern of pressure and wind systems including the monsoon winds in the Indian Ocean. It  is  believed  that  the  severest  droughts in  India  have been caused  by  El-Nino.
• La Nina is thought to be favourable to India as it brings rains.