Indian Monsoon Climate

Climate of India

• Climate refers to the sum total of weather conditions and variations over a large area for a long period of time (more than thirty years).
• Weather refers to the state of the atmosphere over an area at any point of time.

Elements of Weather and Climate

• The elements of weather and climate are the same, i.e.:
• Temperature
• Atmospheric pressure
• Wind
• Humidity
• Precipitation

Monsoon Climate

• The word monsoon is derived from the Arabic word ‘mausim’ which literally means season.
• Early in the season, the windward side of the Western Ghats receives very heavy rainfall, more than 250 cm.
• The Deccan Plateau and parts of Madhya Pradesh also receive some amount of rain in spite of lying in the rain shadow area.
• The maximum rainfall of this season is received in the north-eastern part of the country.
• Mawsynram in the southern ranges of the Khasi Hills receives the highest average rainfall in the world.

Characteristics of Monsoon

• The monsoon rains take place only for a few days at a time.
• They are interspersed with rainless intervals.
• These breaks in monsoon are related to the movement of the monsoon trough.
• When the axis of the monsoon trough lies over the plains, rainfall is good in these parts.
• Whenever the axis shifts closer to the Himalayas, there are longer dry spells in the plains, and widespread rain occur in the mountainous catchment areas of the Himalayan rivers.

Temperature Patterns

• Day temperatures are high, nights are cool and pleasant during the monsoon season.
• The land is still moist.
• Owing to the conditions of high temperature and humidity, the weather becomes rather oppressive during the day, commonly known as ‘October heat’.
• In the second half of October, the mercury begins to fall rapidly in northern India.

Regional Variations

• The Himalayas protect the subcontinent from extremely cold winds from central Asia, enabling northern India to have uniformly higher temperatures compared to other areas on the same latitudes.
• The Peninsular plateau, under the influence of the sea from three sides, has moderate temperatures.
• Despite such moderating influences, there are great variations in the temperature conditions.
• Annual rainfall and temperature variations are different in different cities like Bengaluru, Mumbai, Kolkata, Delhi, Jodhpur, Chennai, Nagpur, Shillong, Thiruvananthapuram, and Leh.