Chapter-Climates of India Social Science class 6 in english Medium CBSE Notes

Chapter 3. Climates of India

1. Weather, Seasons and Climate

Weather is the condition of the atmosphere that we experience over a short period, such as an hour or a day. It keeps changing frequently.

Climate is the pattern of weather experienced by a particular area or region over a long period, usually several decades. Climate varies from region to region.

Seasons

• Seasons occur because the Earth revolves around the Sun.
• Each season lasts for a few months and returns every year.
• Weather changes with the seasons.
• The pattern of seasons in a region is closely connected with its climate.
• Most regions of the world recognise four main seasons – spring, summer, autumn and winter.
• India also experiences a distinct rainy season called the monsoon.

Six Traditional Seasons of India

Season	Meaning
Vasanta	Spring
Grīṣhma	Summer
Varṣhā	Rainy season
Śharad	Autumn
Hemanta	Pre-winter
Śhishir	Winter

Many Indian festivals and rituals are traditionally associated with these six seasons.

2. Diversity of Climate in India

India has a great diversity of climates because of its varied geography, including mountains, deserts, plateaus and coastal regions.

Region	Type of Climate	Main Features
Himalayas	Alpine	Cold and snowy winters with cool summers.
Lower Himalayas and many hill areas	Temperate	Moderately cold winters and relatively mild summers.
Northern Plains	Subtropical	Very hot summers and cold winters.
Thar Desert	Arid	Extremely hot days, cool nights and very little rainfall.
Western Coastal Strip	Tropical Wet	Heavy monsoon rainfall.
Central Deccan Plateau	Semi-arid	Hot summers, mild winters and moderate rainfall.
Eastern India and Southern Peninsula	Tropical	Mild winters with distinct wet and dry periods.

3. Factors Affecting Climate

The climate of a region is determined by the combined effect of several geographical factors.

Latitude

Latitude is the distance of a place north or south of the Equator. It affects the amount of solar energy received by a place.

• Places closer to the Equator are generally warmer.
• Places farther from the Equator are generally cooler.
• Therefore, latitude helps create differences in climate between northern and southern regions.

Altitude

Altitude is the height of a place above sea level.

• Temperature generally decreases as altitude increases.
• High-altitude places are therefore cooler than low-altitude places.
• For example, Ooty is much cooler than nearby Coimbatore even though both are almost at the same latitude.

Proximity to the Sea

The sea acts as a moderator of temperature because land heats and cools faster than water.

• Coastal areas generally have moderate temperatures.
• Summers are not extremely hot near the sea.
• Winters are not extremely cold near the sea.
• Places farther inland experience more extreme temperatures.

Example: Mumbai and Nagpur are at nearly similar latitudes, but Mumbai experiences milder temperatures because it is close to the sea, while Nagpur is inland.

Winds

• Winds carry air from one region to another.
• They can carry warm, cold, dry or moist air.
• Moist winds can bring rainfall.
• Seasonal winds play a particularly important role in India's climate.

Topography

Topography refers to the physical features of the land, such as mountains, hills, valleys and plateaus.

• Mountains can act as barriers to winds.
• The Himalayas help protect the Indian subcontinent from cold winds coming from Central Asia.
• The Western Ghats influence the distribution of monsoon rainfall.
• The flat topography of the Thar Desert allows hot and dry winds to affect the region.

4. Climate and Microclimate

The climate of a region is described using long-term patterns of temperature, precipitation and wind conditions over three decades or more.

Microclimate

A microclimate is the climate of a small area that differs from the climate of the surrounding region.

• Enclosed valleys can have their own microclimates.
• Some forests have microclimates of their own.
• Cities can also develop special local climates.
• Microclimates can influence local plants, animals, crops and human health.

Urban Heat Island

An urban heat island is an urban area that is warmer than the surrounding region.

• Buildings and concrete structures absorb and trap heat.
• Cities with little vegetation can become especially warm.
• Urban heat islands can affect human health and well-being.

5. The Indian Monsoon

The monsoon is a seasonal wind system over a large area of the Indian Ocean and surrounding regions.

The word monsoon comes from the Arabic word mausim, meaning season.

How is the Monsoon Formed?

• Land and water do not heat and cool at the same rate.
• Land heats up and cools down faster than the ocean.
• During summer, the Asian landmass becomes very hot.
• Hot land creates a region of relatively low pressure.
• The nearby ocean remains relatively cooler and has comparatively higher pressure.
• Moist winds therefore move from the ocean towards the land.
• These winds carry moisture and bring rainfall to India.

6. Southwest Monsoon

• The southwest monsoon usually begins from the southern tip of India in early June.
• It moves northwards over several weeks.
• It generally covers the entire Indian subcontinent by mid-July.
• The Western Ghats act as a natural barrier to these winds.
• The western slopes of the Western Ghats receive heavy rainfall.
• The Deccan Plateau on the eastern side receives much less rainfall, often with interruptions.
• It is called the southwest monsoon because the winds come from the southwest.

7. Northeast Monsoon

• During winter, the direction of winds reverses.
• Winds generally blow from the land towards the ocean.
• These winds are generally dry.
• Some winds pass over the Bay of Bengal and collect moisture.
• They bring rainfall to parts of eastern and southern India.
• This is called the northeast monsoon or winter monsoon.

Southwest Monsoon vs Northeast Monsoon

Southwest Monsoon	Northeast Monsoon
Occurs mainly during summer.	Occurs mainly during winter.
Winds generally move from ocean towards land.	Winds generally move from land towards ocean.
Brings large amounts of moisture to India.	Generally consists of dry winds.
Provides most of India's monsoon rainfall.	Brings rainfall to parts of eastern and southern India after crossing the Bay of Bengal.

8. Mawsynram – Highest Rainfall

Mawsynram, located in Meghalaya, receives the highest average annual rainfall in the world.

• It receives about 11,000 mm of average annual rainfall.
• 11,000 mm is equal to about 11 metres of rainfall.

9. Climate and Human Life

• Climate has a strong influence on agriculture.
• Climate affects crop cycles and agricultural production.
• Food habits are influenced by climatic conditions.
• Clothing changes according to temperature and seasons.
• Many festivals and cultural traditions are connected with seasons.
• Climate affects people's livelihoods and economic activities.
• Monsoon rainfall is especially important for Indian agriculture.
• Poor rainfall can cause agricultural losses.
• Water shortages may force people to travel long distances to obtain water.
• Agricultural labourers may migrate to cities when agricultural activity suffers.
• Poor rainfall can make food items more expensive and contribute to inflation.
• Industries also depend on predictable weather and availability of water.

10. Climate and Culture

• Indian cultural traditions are closely connected with seasons and climate.
• Many festivals are associated with particular seasons.
• Monsoon rainfall has inspired Indian music and literature.
• Traditional knowledge has helped communities observe and understand seasonal changes.
• Thus, climate influences not only nature but also the social and cultural life of people.

11. Climate-Related Disasters

India's diverse weather patterns can produce extreme conditions such as cyclones, floods, landslides and forest fires.

• These disasters can cause loss of life.
• They can damage houses, roads and other infrastructure.
• They can affect agriculture and livelihoods.
• They can disturb local economies.

12. Cyclones

A cyclone is an intense low-pressure weather system associated with strong winds, clouds and rainfall.

• India's coastline experiences several cyclones every year.
• The eastern coast is particularly affected.
• Severe cyclones can cause loss of human and animal life.
• They can damage property and infrastructure.
• They can uproot trees and cause soil erosion.

India Meteorological Department (IMD)

The India Meteorological Department (IMD) monitors approaching cyclones and provides information about their formation, development and landfall.

National Disaster Response Force (NDRF)

The National Disaster Response Force (NDRF) is specially trained to respond to natural and human-made disasters.

• NDRF plays an important role in rescue operations.
• It helps in evacuation during disasters.
• It has responded to cyclones, landslides and floods.

13. Floods

A flood occurs when water overflows onto land that is normally dry.

• Floods can occur due to heavy rainfall.
• Rivers and lakes may overflow during periods of excessive rainfall.
• Floods can damage homes, roads, crops and infrastructure.
• Urban flooding can become worse when natural drainage channels are blocked.

14. Landslides

A landslide is the sudden collapse or movement of rock, soil or debris down a slope.

• Heavy rain can trigger landslides.
• Earthquakes and volcanic activity can also trigger landslides.
• Landslides are common in hilly and mountainous regions.
• They are common during the monsoon in many parts of India.
• Cutting down forests can increase the risk of landslides.
• Poorly planned infrastructure can also increase the risk.
• Construction that blocks the natural flow of water can worsen the situation.

15. Forest Fires

A forest fire is an uncontrolled fire that spreads rapidly across vegetation.

• Dry climatic conditions can favour forest fires.
• Drought and high winds can increase their spread.
• Human carelessness is also a frequent cause.
• Forest fires destroy forests and wildlife.
• They degrade ecosystems and reduce air quality.
• They may displace local communities.
• They can cause both environmental and economic damage.

16. Climate Change

Climate change refers to significant long-term changes in climate at a regional or global scale.

• Climate change can involve changes in temperature.
• It can cause changes in precipitation.
• It can influence the frequency or intensity of weather events.
• Natural processes caused climate change in the distant past.
• Since the 19th century, human activities have become a major driver of climate change.

17. Causes of Present-Day Climate Change

• Burning of fossil fuels – Releases large quantities of greenhouse gases.
• Deforestation – Reduces forests and contributes to environmental imbalance.
• Industrial activities – Can release greenhouse gases and other pollutants.
• Transportation – Burning fuels releases greenhouse gases.
• Excessive consumption – Wasteful patterns of production and consumption increase environmental pressure.

18. Greenhouse Effect and Global Warming

The natural greenhouse effect helps keep Earth warm enough to support life.

• Carbon dioxide and other gases naturally occur in the atmosphere.
• These gases trap some heat from the Sun.
• This natural process keeps Earth sufficiently warm.
• Human activities have greatly increased the amount of greenhouse gases in the atmosphere.
• Extra greenhouse gases trap additional heat.
• This causes rapid global warming and disrupts climate patterns.

19. Effects of Climate Change

• Climate change can increase temperatures.
• It can alter rainfall patterns.
• It can increase challenges related to extreme weather.
• Agricultural production can be affected.
• Small-scale industries can also be affected.
• Plants and animals may face changing environmental conditions.
• Human societies may have to adapt to changing climate conditions.

20. Climate Mitigation and Adaptation

Mitigation

Mitigation means adopting measures to slow global warming and reduce the causes of climate change.

• Reducing greenhouse gas emissions.
• Planting more trees.
• Increasing the use of renewable energy.
• Improving energy efficiency.
• Promoting sustainable lifestyles.

Resilience

Resilience is the capacity to withstand difficulties or recover quickly from them.

Sustainable

Sustainable means something that can be maintained over a long period of time.

Important Definitions

Term	Definition
Weather	The atmospheric condition experienced over a short period such as an hour or a day.
Climate	The long-term pattern of weather experienced by a region over several decades.
Season	A period of the year with characteristic weather conditions that recurs every year.
Latitude	The distance of a place north or south of the Equator.
Altitude	The height of a place above sea level.
Topography	The physical features of the surface of an area, such as mountains, hills, valleys and plateaus.
Monsoon	A seasonal wind system that changes direction with the seasons.
Microclimate	The climate of a small area that differs from the surrounding region.
Urban Heat Island	An urban area that is warmer than its surrounding region because buildings and concrete structures trap heat.
Cyclone	An intense low-pressure weather system with strong winds, clouds and rainfall.
Flood	A situation in which water overflows onto land that is normally dry.
Landslide	The sudden collapse or movement of rock, soil or debris down a slope.
Forest Fire	An uncontrolled fire that spreads rapidly across vegetation.
Climate Change	Significant long-term changes in climate involving temperature, precipitation or weather events.
Fossil Fuels	Sources of energy formed from the remains of plants and animals buried millions of years ago, such as coal, petroleum and natural gas.
Greenhouse Effect	The natural process in which gases in the atmosphere trap heat and keep Earth warm enough for life.
Resilience	The capacity to withstand difficulties or recover quickly from them.
Mitigation	Steps taken to slow global warming and reduce the causes of climate change.
Sustainable	Something that can be maintained over a long period of time.

Important Differences

Weather and Climate

Weather	Climate
Short-term condition of the atmosphere.	Long-term pattern of weather.
Can change from hour to hour or day to day.	Changes over a much longer period.
Example: Today's rainfall.	Example: The usual rainfall pattern of a region.

Southwest Monsoon and Northeast Monsoon

Southwest Monsoon	Northeast Monsoon
Summer monsoon.	Winter monsoon.
Generally moves from ocean to land.	Generally moves from land to ocean.
Brings most of India's monsoon rainfall.	Brings rainfall to parts of eastern and southern India.

Coastal Climate and Inland Climate

Coastal Climate	Inland Climate
Temperature is more moderate.	Temperature is more extreme.
Summers are generally less hot.	Summers can be very hot.
Winters are generally milder.	Winters can be much colder.
Sea moderates temperature.	Greater distance from sea increases temperature variation.

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