Learning Objective
- Climatic Controls
- Factors Affecting India’s Climate
- The Seasons
- Distribution of Rainfall
- Monsoon as a Unifying Bond
- 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 in time.
The elements of weather and climate are the same, i.e. temperature, atmospheric pressure, wind, humidity and precipitation. On the basis of the monthly atmospheric conditions, the year is divided into seasons such as:
- Winter
- Summer
- Rainy Seasons
Climatic Controls
The climate of any place depends on the following factors:
- Latitude: Solar energy varies with latitude. Air temperature decreases from the equator to the poles.
- Altitude: Higher altitude means cooler temperatures due to thinner air.
- Pressure and Wind: Latitude and altitude influence pressure and wind patterns, affecting temperature and rainfall.
- Distance from the Sea: Proximity to the sea moderate’s climate. Greater distance leads to extreme conditions (continentality).
- Ocean Currents: Coastal climate is influenced by warm or cold ocean currents and onshore winds.
- Relief Features: Mountains block winds and cause precipitation. Precipitation includes rain, snow, hail, and sleet.
Factors Affecting India’s Climate
Latitude
- The Tropic of Cancer passes through the middle of the country from the Rann of Kachchh in the west to Mizoram in the east. India’s climate has characteristics of tropical as well as subtropical climates.
Altitude
- India has mountains to the north and also has a vast coastal area where the maximum elevation is about 30 metres. Owing to the mountains, the subcontinent experiences comparatively milder winters as compared to central Asia.
Pressure and Winds:
- During winter, a high-pressure area exists north of the Himalayas. Cold, dry winds blow from this region toward the low-pressure areas over the oceans in the south.
- In summer, the situation reverses. A low-pressure area develops over northwestern India and the interior of Asia. The winds now blow from the south, bringing moisture from warm oceans. These are the Southwest Monsoon winds, responsible for widespread rainfall across India
Jet streams are fast-flowing, narrow, meandering air currents in the atmosphere.
The Seasons
4 main seasons can be identified in India:
- The cold weather season (Winter)
- The hot weather season (Summer)
- The advancing monsoon (Rainy Season)
- The retreating monsoon with some regional variations (Transition Season)
The Cold Weather Season (Winter)
Winter begins in mid-November in northern India and stays till February.
- December and January are the coldest months in the northern part of India.
- The temperature decreases from the south to the north.
- Days are warm and nights are cold.
- The weather is marked by clear sky, low temperatures and low humidity and feeble, variable winds.
- This season is extremely important for the cultivation of ‘rabi’ crops.
Hot Weather Season (Summer):
- Occurs from March to May.
- Rising temperatures and falling air pressure in northern India.
- Notable feature: ‘loo’—strong, gusty, hot, dry winds during the day in the north and northwest.
- Pre-monsoon showers, known as ‘mango showers’, aid early mango ripening.
Advancing Monsoon (The Rainy Season)
- South-East Trade Winds:
- Originate over warm subtropical areas in the southern oceans.
- Cross the equator and blow southwestward into the Indian peninsula as the Southwest Monsoon. These winds cover India for about a month.
- Mawsynram:
- Located in the southern Khasi Hills.
- Receives the highest average rainfall in the world.
- Breaks in Monsoon:
- Associated with the movement of the monsoon trough. Trough axis determines spatial rainfall distribution.
- Tropical depressions impact monsoon intensity, duration, and uncertainty.
Retreating/Post Monsoons (The Transition Season)
- October-November Transition:
Monsoon Retreat:
- Clear skies and rising temperatures.
- Days are hot, nights cool and pleasant.
- ‘October heat’: Oppressive daytime conditions due to high temperature and humidity.
Second Half of October:
- Mercury rapidly falls in northern India as winter approaches.
Distribution of Rainfall
- Parts of the western coast and northeastern India receive over about 400 cm of rainfall annually.
- Rainfall is less than 60 cm in western Rajasthan and adjoining parts of Gujarat, Haryana and Punjab.
- Rainfall is low in the interior of the Deccan plateau and east of the Sahyadris.
- Snowfall is restricted to the Himalayan region.
- The annual rainfall is highly variable from year to year.
Monsoon as a Unifying Bond
“Monsoons in India bring rhythmic seasons, eagerly awaited by people across the country. These winds provide vital water for agricultural activities.”
Why CBSEJanta.com for Class 9 Social Science?
- Detailed Chapter Solutions: Get comprehensive solutions for every chapter in History, Geography, Civics, and Economics.
- Important Concepts and Key Points: Concise notes on crucial concepts to aid in understanding and revision.
- Extra Practice Questions: Practice your learning with extra questions and answers based on the latest syllabus.
- Interactive Learning: Audio-visual explanations for better grasp of challenging topics.
Download the CBSEJanta App Now!
Download the CBSEJanta App Now!
With CBSEJanta.com, understanding Social Science has never been easier! 📚✨ Get FREE chapter-wise solutions, summaries, key concepts, and practice exercises to boost your exam preparation.
Visit CBSEJanta.com or download the CBSEJanta app today for a smarter, easier learning experience.
This structured post gives a subject-wise breakdown for Class 9 Social Science, making it easy for students to understand the chapters while encouraging them to use CBSEJanta.com for comprehensive learning and exam preparation.