Class 9 Geography Climate Notes NCERT Chapter 4

CBSE Geography chapter 4 Climate is very important for students for class 9 students. The students can use this Climate notes to prepare for examination. the Climate class 9 notes helpful for students to revise quickly. The notes are based on latest NCERT Class 9 geography.

Weather is the change of atmospheric conditions for a short period. The variation in weather conditions for a consistently long time. The change in weather conditions and variations over a large area over a long period of time such as 30-35 years. The elements of weather are rainfall, wind, atmospheric pressure, and temperature. The atmospheric conditions that change daily are called weather and the weathering condition that sustains for a long period is called the climate of a place.

The climate of India mainly dominated by monsoon. India experiences differential climate variation. India receives 20 cm of annual rainfall in northwestern Rajasthan and Gujarat. Arunachal Pradesh and Assam receive above 250 cm of rainfall. Mawsynram in Meghalaya receives 11,872 millimeters annually. During winter, the temperature fall below -40°C, while Thirunthampuram experiences 45°C on the same night. These climatic variations change the lifestyle and living standard of people in India.

Factors that affect the climate of India Class 9 Climate Notes

1. Latitude: The Tropic of Cancer passes India 23.5°N. The Tropic of Cancer runs through India from Gujarat in the west to Mizoram in the east. The latitude ‘Tropic of cancer’ divides India into two halves. India’s northern region lies in the tropical region and India’s south lies in tropical regions. Due to vertical rays that fall on the equator of the Earth in result India experiences high temperatures.
2. Altitude: The temperature decreases with increasing height. As we know northern mountain has low temperature due to massive altitude. The perennial snowfall can be observed. The temperature decreases by 1°C with an increasing height of 165 m above the sea level.
3. Air pressure and surface winds: The northeastern winds blow over land carry minute moisture and cause no rainfall.
   • During winter season The Himalayan region experiences high atmospheric pressure. The high pressure causes strong cold winds to blow southward over the oceans.
   • During the summer season, the central part of Asia experiences low pressure, and the winds completely reverse itself. The wind flows from areas of high pressure to areas of low pressure.
   • The Subtropical westerly jet streams influenced India’s climate. The northern and northwestern states were disturbed by the western cyclone.
4. Relief features: Jet streams blow from high altitudes also known as westerly winds in the first layer of the atmosphere. The velocity of jet streams changes with the seasons; in summer, it blows at 110 km/h, while in winter, the speed increases to 184 km/h. The disturbances experienced in the northern and northern western states of India were caused by jet streams.

The Monsoon climate in India Weather and Climate Class 9 Notes

The Monsoon climate in India is caused by Monsoon winds from the south. The students should remember important key points to continue the monsoon season in India.

1. India is a peninsular plateau that experiences extremely high temperatures in the north and low temperatures in the south.
2. India’s mainland experiences heating and cooling effects due to extreme sun’s heat.
3. The land experiences low atmospheric pressure caused by the heating, meanwhile, the seas experience high pressure due to sunlight. This is where the land breeze and sea breeze normalize the temperature in day and night respectively.
4. Inter-tropical Convergent Zone (ITCZ) is the trough that experiences low pressure on the equatorial latitude.
5. The Indian monsoon is also affected by Madagascar due to the high-pressure region.
6. The fast-moving jet streams to the northern Himalayas and the tropical easterly winds towards the south stream over the peninsula affect rainfall in India.

Indian Monsoon Class 9 Climate notes NCERT

The monsoon in India is attributed to the following reasons:

1. The differential heating and cooling of land and water create a low-pressure zone over the land. The marine regions like the sea and ocean result in high pressure.
2. Intertropical convergent zones are a wide trough of low pressure in the equatorial pressure.
3. Madagascar in the east experiences high-pressure effects of Indian monsoon
4. The jet streams that flow over the Indian Deccan and central highlands plateau and the westerly winds that blow from the northern Himalayas.
5. The sudden changes due to excessive heating and cooling in the Southern Ocean also affect monsoons.
6. When the eastern South Pacific Ocean experiences high pressure then the Indian tropical eastern India experiences low pressure.
7. Pressure conditions also reverse due to the movement of oceanic water from high-pressure to low-pressure belts.
8. The momentous change in pressure conditions is known as southern oscillation.

The Onset of Monsoons and their Withdrawal

In India, June to mid-September is the duration of the monsoon season. This phenomenon is known as a burst in the monsoon season. In the first week of June, the monsoon arrives in the western ghat (Kerela). The Arabian Sea branch reaches the Mumbai coast region in the second week of June. The Bay of Bengal reaches Assam in the first week of June. The mountains act as the deflection of rain-bearing monsoon clouds over northern plains. The monsoon also Strick the Madhya Pradesh, Gujarat, Chhattisgarh and Odisha (Central states of India). The northern plains, including Uttar Pradesh, Haryana, and eastern Rajasthan, typically experience rainfall during the first or second week of June. The withdrawal of northwestern winds begins in early September. In mid-October, the wind withdraws to the peninsular plateau by the first week of December.

The Season in India Climate Chapter Class 9 Notes

India is unique in seasonal variation as compared to other countries. Each season is influenced by India’s geography and the shifting position of the sun and monsoon winds.

The Cold weather season in India

1. As mid-November arrives, India steps into the enchanting chill of winter, lasting until mid-March.
2. In the cold western season, the days are a little warmer, and nights are chilling cold about 4 C.
3. Most of the Indian region remains dry during the cold weather season. Northeast trade winds blow from the mainland to the sea.
4. In northern India cyclonic distribution during this time.
5. Minor rainfall occurs in northern regions are parental snowfall excessively falls on the Himalayan mountains.
6. In the winter season, India grows rabi crops such as wheat and mustard seeds.

The Hot weather season in India

1. From March of every year, the hot weather starts in India till mid-July. In the northern part of India low pressure belt is caused by a high rise in temperature.
2. The local winds that occur during the summer season are referred to as “loo.” The loo causes skin burns, depression, and fever.
3. In north India, people experience dust storms that come with rain showers. The rain showers and fast-moving winds lower the temperature, and this also known as ‘Kaal Baishakhi’.
4. The heavy rain in West Bengal is accompanied by hail.
5. When the summer season ends the orographically rainfall is common in Kerela and Karnataka due to western ghat hills.
6. The rainfall helps in the ripening of fruits such as mangoes and watermelon, although this is known as a mango shower.

Advancing Monsoon in India

1. In the first week of June, pressure conditions get intense in north India and attract southeast trade winds that start from the Indian oceans.
2. The winds blow from warmer oceanic currents and bring moisture and rainfall to the west coastal region of India.
3. When the monsoon starts in India the western ghat receives 250 cm of heavy rainfall due to the leeward side (orographic rainfall)
4. The northeastern states like Meghalaya, Arunachal Pradesh, Assam, Tripura, and other states receive heavy rainfall due to low elevated mountains. Maywsynram in east Khasi hills is a region in Meghalaya state that receives 390 cm of rainfall annually.
5. When we go east to west parallel the India the rainfall decreases. The western part of Rajasthan and Gujarat receives low rainfall.
6. Rain does not fall throughout the month of monsoon season thus falls in dry and wet spells. In India, monsoons are uncertain and irregular.

Retreating Monsoon in India

1. During the initial months of October and November, the monsoon winds from the southwest become weaker and start retreating from the northern plains by mid-October.
2. During this time, the low-pressure condition resulted in a cyclonic depression in the Bay of Bengal and even the then the eastern coastal plains.
3. The Coromandel coast experiences low pressure which results in cyclonic depression.

Distribution of Rainfall in India

India experiences irregular and uncertain rainfall distribution. In contrast, the western parts of Gujarat and Rajasthan receive low rainfall, averaging around 66 cm, due to sparse vegetation and desert conditions. The rainfall winds that originate from the Arabian Sea are moisture-laden winds.

1. The Arabian Sea winds met with the western Ghats mountains heavy rain due to irregular mountain ranges.
2. In the eastern ghats, the rainfall remains low due to the low elevation mountain. Jammu Kashmir (Leh region) receives low rainfall.
3. The central part of India receives moderate rainfall.
4. In India, such varied distribution of rainfall shows great climatic variation.
5. The Northeastern states of India receive heavy rainfall. The Northeastern region always gets flooded every year due to heavy rainfall.
6. The western part such as Rajasthan and Gujarat receives low rainfall throughout the year.

The Unifying Bond – Monsoon

As we know monsoon in India is irregular and uncertain in India. These variations unify the entire country. In India most of the farmers still dependent on monsoon to irrigate their agricultural fields. In India, people used to celebrate when the monsoon arrived by singing, dancing, and group celebration.

Read More:

CBSE Class 9 Physical Feature of India Notes

Class 9 Geography India Size and Location Notes

Frequently Asked Questions from Class 9 Geography Chapter 4: Climate (NCERT)

Question 1. What is the difference between weather and climate according to the Class 9 NCERT Geography textbook?

Answer: Weather varies from day to day, but climate shifts develop gradually over time

Question 2. Why does India have diverse climatic conditions as per NCERT Chapter 4 Climate?

Answer: India has diverse climate conditions due to regional variations of landforms and monsoon dominated climatic conditions in India.

Question 3. What is the role of monsoon in Indian agriculture as discussed in the Class 9 Geography Climate chapter?

Answer: Farmers in India are heavily dependent on monsoon rainfall to irrigate their agricultural fields and other activities