Class 9 : Social Science (In English) – Lesson 14. Climate
EXPLANATION & SUMMARY
🌍 1. Introduction: India’s Climate Diversity
🌡️ India has a monsoon type of climate with regional variations.
🟢 Broad unity: seasonal rhythm → summer, winter, rainy, retreating monsoon.
🌍 Influenced by tropic–temperate location, Himalayas, oceans, monsoon winds.
🌞 2. Factors Affecting Climate of India
🗺️ (i) Latitude
Northern part → subtropical climate.
Southern part → tropical climate.
Tropic of Cancer divides India → two distinct zones.
🌊 (ii) Altitude
Mountains cooler; plains hotter.
Example: Shimla vs Delhi in summer → temp difference due to height.
🌊 (iii) Distance from Sea (Continentality)
Coastal regions (Mumbai, Chennai) → equable climate.
Interior regions (Delhi, Nagpur) → extreme climate (hot summers, cold winters).
🌬️ (iv) Relief
Himalayas protect northern plains from cold Siberian winds.
Western Ghats cause orographic rainfall on windward side.
💨 (v) Monsoon Winds
Main controller of climate.
Southwest monsoon → brings rain.
Northeast monsoon → retreating phase.
🌍 (vi) Jet Streams
Subtropical westerly jet → western disturbances in winter.
Easterly jet → onset of monsoon.
🔥 3. Seasons in India
🌞 (i) Cold Weather Season (Winter) → Dec–Feb
🌡️ Temp: ~10–15°C in north, higher in south.
🌬️ Dry northeast trade winds prevail.
🌧️ Western disturbances bring rain in Punjab, Haryana; snow in Himalayas.
☀️ (ii) Hot Weather Season (Summer) → Mar–May
🌡️ High temps: 38–45°C in north, ~30°C in south.
🌪️ Local hot winds → loo in north.
🌧️ Nor’westers (Kalbaisakhi) in Bengal, Assam bring rain + storms.
🌧️ (iii) Advancing Monsoon (Rainy Season) → June–Sept
💨 SW monsoon enters Kerala (1 June).
🌊 Divided into Arabian Sea & Bay of Bengal branches.
🌱 Rainfall → agriculture lifeline.
⛈️ Unequal distribution: Meghalaya’s Mawsynram = heaviest; Rajasthan desert = arid.
🍂 (iv) Retreating/Post-Monsoon → Oct–Nov
🌬️ Monsoon withdraws → clear skies, rising temps.
🌧️ Northeast monsoon brings rain to Tamil Nadu, Andhra.
🌀 Tropical cyclones affect east coast.
🌡️ 4. Monsoon Mechanism
🔵 Differential heating of land and sea → pressure gradient.
🟢 ITCZ (Inter-Tropical Convergence Zone) shifts north in summer → low pressure.
🌊 Trade winds cross equator → deflected SW → monsoon winds.
🌬️ Tibetan Plateau + Himalayas intensify low pressure.
📡 Jet streams influence onset and retreat.
🌍 5. Distribution of Rainfall
🌧️ Heavy (>200 cm): Western Ghats, NE states.
🌦️ Moderate (100–200 cm): Northern plains, coastal Andhra.
🌵 Low (<50 cm): Rajasthan desert, Ladakh.
🏞️ Uneven rainfall → floods in Assam/Bihar, droughts in Rajasthan/Gujarat.
⚔️ 6. Monsoon as a Unifying Bond
🌱 Agriculture across India depends on monsoon rains.
🕌 Festivals (Onam, Pongal, Baisakhi) linked with monsoon.
🌍 Shared cultural rhythm → unity despite diversity.
🌳 7. Challenges & Climate Change
🌡️ Variability → floods, droughts, cyclones.
🌍 Climate change → rising temps, shifting monsoon.
🌱 Need for forecasting, conservation, adaptation.
📝 Summary (~200 words)
India has a monsoon type of climate influenced by latitude, altitude, distance from sea, relief, monsoon winds, and jet streams. The Himalayas shield northern India from cold winds, while oceans moderate coastal climate.
India experiences four seasons:
Winter → cool, dry, with western disturbance rains.
Summer → hot, with loo winds and Nor’westers.
Rainy season → advancing SW monsoon, uneven rainfall.
Retreating monsoon → withdrawal, cyclones, NE monsoon rains in Tamil Nadu.
The monsoon mechanism involves ITCZ shift, differential heating, and seasonal wind reversal. Rainfall distribution is highly uneven, causing floods in some regions and drought in others. Despite this, the monsoon acts as a unifying bond, connecting agriculture, festivals, and livelihoods. Climate change now poses challenges, requiring sustainable solutions.
⚡ Quick Recap (~100 words)
🌡️ Climate: Monsoon type with regional variations.
🗺️ Factors: Latitude, altitude, sea distance, relief, winds, jet streams.
❄️ Winter: Cold, dry, western disturbances.
☀️ Summer: Hot, loo winds, Nor’westers.
🌧️ Rainy: SW monsoon, uneven rainfall.
🍂 Retreating: NE monsoon, cyclones.
🌍 Monsoon mechanism: ITCZ, land–sea heating, Himalayas.
📊 Rainfall: Heavy in NE/West coast, low in desert/Ladakh.
🤝 Unifying bond: Agriculture, festivals, culture.
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QUESTIONS FROM TEXTBOOK
🔵 Question 1. Choose the correct answer from the four alternatives given below.
(i) Which one of the following places receives the highest rainfall in the world?
(A) Silchar
(B) Cherrapunji
(C) Mawsynram
(D) Guwahati
🟢 Answer: (C) Mawsynram
(ii) The wind blowing in the northern plains in summers is known as:
(A) Kaal Baisakhi
(B) Trade Winds
(C) Loo
(D) None of the above
🟢 Answer: (C) Loo
(iii) Monsoon arrives in India approximately in:
(A) Early May
(B) Early June
(C) Early July
(D) Early August
🟢 Answer: (B) Early June
(iv) Which one of the following characterises the cold weather season in India?
(A) Warm days and warm nights
(B) Warm days and cold nights
(C) Cool days and cold nights
(D) Cold days and warm nights
🟢 Answer: (C) Cool days and cold nights
🔵 Question 2. Answer the following questions briefly.
(i) What are the controls affecting the climate of India?
🟢 Answer:
🌡️ Latitude (tropical south, subtropical north).
🏔️ Altitude (Himalayas cooler, plains hotter).
🌊 Distance from sea (coastal → equable, interior → extreme).
⛰️ Relief features (Himalayas, Western Ghats).
💨 Winds (monsoons, westerlies).
📡 Jet streams & pressure systems.
(ii) Why does India have a monsoon type of climate?
🟢 Answer:
🌍 Location: tropical–subtropical zone.
🌡️ Seasonal reversal of winds due to land–sea heating difference.
🏔️ Himalayas block cold winds and guide monsoon.
🌊 Oceans provide moisture for rainfall.
(iii) Which part of India does experience the highest diurnal range of temperature and why?
🟢 Answer:
🌵 Northwest desert (Thar Desert, Rajasthan).
🌡️ Day = very hot, Night = rapid cooling.
🏜️ Due to arid climate, clear skies, low humidity.
(iv) Which winds account for rainfall along the Malabar coast?
🟢 Answer:
🌊 Southwest monsoon winds (Arabian Sea branch).
🌧️ Cause orographic rainfall on Western Ghats.
(v) Define monsoons. What do you understand by “break” in monsoon?
🟢 Answer:
💨 Monsoon = seasonal reversal of winds.
🌧️ Break in monsoon = dry intervals when rain pauses after heavy showers, due to shifting monsoon trough.
(vi) Why is the monsoon considered a unifying bond?
🟢 Answer:
🌱 Provides water for agriculture across India.
🕌 Festivals and traditions linked with rains.
👥 Shared cultural rhythm and livelihood cycle.
🌍 Connects diverse regions in one seasonal pattern.
🔵 Question 3. Why does the rainfall decrease from the east to the west in Northern India?
🟢 Answer:
🌧️ Monsoon winds from Bay of Bengal lose moisture as they move west.
🏞️ Eastern states (Bengal, Bihar) → heavy rainfall.
🌵 Western states (Rajasthan, Punjab) → low rainfall.
🔵 Question 4. Give reasons as to why:
(i) Seasonal reversal of wind direction takes place over the Indian subcontinent?
🟢 Answer:
🌡️ Land heats faster in summer → low pressure.
🌊 Sea cooler → high pressure.
🌍 Winter = opposite pattern.
🔄 This causes seasonal wind reversal = monsoon.
(ii) The bulk of rainfall in India is concentrated over a few months.
🟢 Answer:
🌧️ ~75% rainfall comes in June–Sept.
💨 Due to SW monsoon dominance.
⏳ Other months mostly dry.
(iii) The Tamil Nadu coast receives winter rainfall.
🟢 Answer:
🌬️ NE monsoon winds blow from land to sea.
🌊 They pick up moisture from Bay of Bengal.
🌧️ Bring rain to Tamil Nadu, Andhra.
(iv) The delta region of the eastern coast is frequently struck by cyclones.
🟢 Answer:
🌊 Retreating monsoon season (Oct–Nov).
🌀 Low-pressure systems form in Bay of Bengal.
🚨 Cyclones strike Andhra, Odisha, Bengal coasts.
(v) Parts of Rajasthan, Gujarat and the leeward side of the Western Ghats are drought-prone.
🟢 Answer:
🌵 Arid climate, very little rainfall.
🏔️ Western Ghats → rain shadow on leeward side.
🌍 Monsoon winds lose moisture before reaching these regions.
🔵 Question 5. Describe the regional variations in the climatic conditions of India with the help of suitable examples.
🟢 Answer:
🌡️ Jaisalmer (Rajasthan): Hot desert, extreme temperatures.
🌧️ Mawsynram (Meghalaya): Heaviest rainfall in world.
🏔️ Leh (Ladakh): Cold desert, scanty rainfall.
🌊 Mumbai/Kochi: Equable maritime climate.
❄️ Drass (J&K): Severe cold in winter.
🔵 Question 6. Give an account of weather conditions and characteristics of the cold season.
🟢 Answer:
🌡️ Temp ~10–15°C in north plains, higher in south.
🌬️ Cold, dry winds blow.
🌧️ Western disturbances → winter rain in Punjab/Haryana.
❄️ Snowfall in Himalayas.
🌞 Clear skies, low humidity.
🔵 Question 7. Give the characteristics and effects of the monsoon rainfall in India.
🟢 Answer:
🌧️ Irregular, uncertain, unevenly distributed.
⛈️ Heavy downpours → floods (Assam, Bihar).
🌵 Deficiency → droughts (Rajasthan, Gujarat).
🌱 Basis of agriculture (75% rainfall in 4 months).
🤝 Acts as cultural + economic unifier.
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OTHER IMPORTANT QUESTIONS FOR EXAMS
🌟 SECTION A — Multiple Choice Questions (1 mark each)
🔵 Q1. Which place receives the highest rainfall in the world?
(A) Silchar
(B) Cherrapunji
(C) Mawsynram
(D) Guwahati
🟢 Answer: (C) Mawsynram
🔵 Q2. The hot, dry wind blowing in northern plains during summer is:
(A) Kaal Baisakhi
(B) Trade Winds
(C) Loo
(D) None of these
🟢 Answer: (C) Loo
🔵 Q3. Monsoon arrives in India approximately in:
(A) Early May
(B) Early June
(C) Early July
(D) Early August
🟢 Answer: (B) Early June
🔵 Q4. Which condition characterises the cold weather season in India?
(A) Warm days and warm nights
(B) Warm days and cold nights
(C) Cool days and cold nights
(D) Cold days and warm nights
🟢 Answer: (C) Cool days and cold nights
🔵 Q5. Which winds bring winter rainfall to north-western India?
(A) Trade Winds
(B) Western Disturbances
(C) Jet Streams
(D) Monsoon Winds
🟢 Answer: (B) Western Disturbances
🔵 Q6. Retreating monsoon winds cause heavy rainfall in:
(A) Kerala
(B) Tamil Nadu
(C) Rajasthan
(D) Punjab
🟢 Answer: (B) Tamil Nadu
🔵 Q7. Which winds are responsible for rainfall along the Malabar coast?
(A) Arabian Sea branch of SW monsoon
(B) Bay of Bengal branch of SW monsoon
(C) Northeast monsoon winds
(D) Westerlies
🟢 Answer: (A) Arabian Sea branch of SW monsoon
🔵 Q8. Which factor prevents cold Siberian winds from entering India?
(A) Aravallis
(B) Himalayas
(C) Deccan Plateau
(D) Vindhyas
🟢 Answer: (B) Himalayas
🔵 Q9. Which cyclone-prone region in India is most frequently affected?
(A) Western Coast
(B) Eastern Coast (Bay of Bengal)
(C) Northern Plains
(D) Desert region
🟢 Answer: (B) Eastern Coast (Bay of Bengal)
🔵 Q10. Which of these controls does NOT affect the climate of India?
(A) Latitude
(B) Altitude
(C) Distance from sea
(D) Ocean currents
🟢 Answer: (D) Ocean currents
🔵 Q11. Which month marks the retreat of the southwest monsoon?
(A) September
(B) October
(C) November
(D) December
🟢 Answer: (B) October
🔵 Q12. Which region in India experiences the highest diurnal temperature range?
(A) Rajasthan desert
(B) Kerala coast
(C) Assam plains
(D) Deccan plateau
🟢 Answer: (A) Rajasthan desert
🔵 Q13. Which local storm is called “Kalbaisakhi”?
(A) Rajasthan desert storm
(B) Nor’wester in Bengal and Assam
(C) Loo in northern plains
(D) Cyclone in Andhra Pradesh
🟢 Answer: (B) Nor’wester in Bengal and Assam
🔵 Q14. Which jet stream influences western disturbances in winter?
(A) Easterly Jet
(B) Subtropical Westerly Jet
(C) Polar Jet
(D) Equatorial Jet
🟢 Answer: (B) Subtropical Westerly Jet
🔵 Q15. Which of these areas is rain-shadow due to Western Ghats?
(A) Mumbai
(B) Goa
(C) Tamil Nadu interior
(D) Kerala coast
🟢 Answer: (C) Tamil Nadu interior
🔵 Q16. Which is the wettest place in India?
(A) Cherrapunji
(B) Mawsynram
(C) Shillong
(D) Kohima
🟢 Answer: (B) Mawsynram
🔵 Q17. Which region receives winter rainfall from western disturbances?
(A) Northern plains
(B) Western coastal plains
(C) Deccan plateau
(D) Eastern Himalayas
🟢 Answer: (A) Northern plains
🔵 Q18. What is meant by “break” in monsoon?
(A) Continuous rainfall
(B) Rainfall stops for some time
(C) Shift in ITCZ
(D) Early withdrawal
🟢 Answer: (B) Rainfall stops for some time
🔵 Q19. Which factor is mainly responsible for onset of monsoon in India?
(A) Land–sea heating contrast
(B) Ocean currents
(C) Continentality
(D) El Niño effect
🟢 Answer: (A) Land–sea heating contrast
🌟 SECTION B — Very Short Answer (2 marks each)
🔵 Q20. What are the controls affecting the climate of India?
🟢 Answer:
🌡️ Latitude → tropical south, subtropical north.
🏔️ Altitude → mountains cooler, plains hotter.
🌊 Distance from sea → coastal equable, interior extreme.
⛰️ Relief → Himalayas, Ghats influence rainfall.
💨 Winds + Jet streams.
🔵 Q21. Why does India have a monsoon type of climate?
🟢 Answer:
🌍 Location in tropical/subtropical zone.
🌡️ Seasonal land–sea heating difference.
🏔️ Himalayas blocking cold winds.
🌊 Surrounding oceans supply moisture.
🔵 Q22. Which part of India experiences highest diurnal range of temperature? Why?
🟢 Answer:
📍 Thar Desert, Rajasthan.
🌡️ Hot days, rapid cooling at night.
🌵 Clear skies + dry air cause extremes.
🔵 Q23. Which winds account for rainfall along the Malabar Coast?
🟢 Answer:
🌊 Arabian Sea branch of SW monsoon.
⛰️ Cause orographic rainfall on windward Ghats.
🌟 SECTION C — Short Answer (3 marks each)
🔵 Q24. Define monsoons. What do you understand by “break” in monsoon?
🟢 Answer:
💨 Monsoon = seasonal reversal of winds.
🌧️ “Break” = temporary pause in rain after heavy showers, due to monsoon trough shifting.
🔵 Q25. Why is the monsoon considered a unifying bond?
🟢 Answer:
🌱 Agriculture across India depends on monsoon rains.
🕌 Festivals and traditions tied to rainfall.
👥 Shared economic + cultural rhythm despite diversity.
🔵 Q26. Why does rainfall decrease from east to west in Northern India?
🟢 Answer:
🌧️ Monsoon winds from Bay of Bengal lose moisture as they move west.
🏞️ East (Bengal, Bihar) → heavy rain.
🌵 West (Rajasthan, Punjab) → less rain.
🔵 Q27. Give two features each of the summer and winter season in India.
🟢 Answer:
☀️ Summer: High temps (38–45°C north), loo winds, Kalbaisakhi storms.
❄️ Winter: Cool dry winds, western disturbances, snow in Himalayas.
🔵 Q28. Why is Tamil Nadu coast wet during retreating monsoon?
🟢 Answer:
🌬️ NE monsoon picks moisture from Bay of Bengal.
🌧️ Brings rainfall to Tamil Nadu in Oct–Nov.
🌟 SECTION D — Long Answer (5 marks each)
🔵 Q29. Describe the regional variations in the climate of India with examples.
🟢 Answer:
🌵 Jaisalmer → arid desert, extreme heat.
🌧️ Mawsynram → world’s heaviest rainfall.
🏔️ Leh → cold desert, scanty rainfall.
🌊 Mumbai/Kochi → equable maritime.
❄️ Drass → severe cold in winter.
🔵 Q30. Give an account of weather conditions and characteristics of the cold season.
🟢 Answer:
🌡️ Avg temp 10–15°C in north plains.
🌬️ Cold, dry northeast trades.
🌧️ Western disturbances → rain Punjab/Haryana.
❄️ Snowfall in Himalayas.
🌞 Clear skies, low humidity.
🔵 Q31. Give characteristics and effects of monsoon rainfall in India.
🟢 Answer:
🌧️ Uneven distribution: floods in Assam, droughts in Rajasthan.
🌱 75% rainfall in 4 months → agri lifeline.
⛈️ Erratic → uncertainty for farmers.
🤝 Creates cultural unity and economic dependence.
🔵 Q32. Explain why seasonal reversal of wind direction takes place over India.
🟢 Answer:
🌡️ Summer: land heats faster → low pressure.
🌊 Sea cooler → high pressure → SW monsoon.
❄️ Winter: land cools faster → high pressure.
🌍 Sea relatively warmer → NE monsoon.
🌟 SECTION E — Case/Source-Based (4 marks each)
🔵 Q33. Case: A farmer in Punjab benefits from unexpected winter rain.
(i) Which winds cause it? (1)
(ii) How does it help crops? (1)
(iii) State two crops that benefit. (2)
🟢 Answer:
(i) 🌬️ Western disturbances.
(ii) 🌱 Provide moisture in winter.
(iii) 🌾 Wheat, mustard.
🔵 Q34. Case: A cyclone strikes Odisha coast in October.
(i) Which season is this? (1)
(ii) Which coast is cyclone-prone? (1)
(iii) Suggest two safety measures. (2)
🟢 Answer:
(i) 🍂 Retreating monsoon.
(ii) 🌊 Eastern coast (Bay of Bengal).
(iii) ✅ Early warning, cyclone shelters.
🔵 Q35. Source: News reports Mawsynram as the wettest place.
(i) Which state is it in? (1)
(ii) Which winds cause rain there? (1)
(iii) State two impacts of such heavy rain. (2)
🟢 Answer:
(i) 📍 Meghalaya.
(ii) 🌬️ Bay of Bengal branch of SW monsoon.
(iii) 🌱 Fertile soil, but ⚠️ landslides/floods.
🌟 SECTION F — Map/Skill (5 marks)
🔵 Q36. On an outline map of India, locate and label:
🟢 Answer:
📍 Mawsynram
📍 Chennai (NE monsoon rainfall)
📍 Rajasthan Desert
📍 Western Ghats
🔵 Q37. For visually impaired candidates: Name four features showing climatic diversity of India.
🟢 Answer:
🌵 Thar Desert (hot, arid).
🌧️ Mawsynram (wettest place).
❄️ Leh/Drass (cold desert).
🌊 Kochi/Mumbai (equable maritime climate).
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