Climate – Class 9 Geography Notes
1. Weather vs. Climate
Weather: Condition of the atmosphere at a particular place and time (short period – day
to day).
Example: Today is sunny, tomorrow may rain.
Climate: The average weather condition of a place over a long period (30–35 years).
Example: India has a monsoon type of climate.
2. Factors Affecting Climate of India
1. Latitude –
o Tropic of Cancer passes through India.
o Northern part → temperate climate; Southern part → tropical climate.
2. Altitude –
o Places at higher altitude (Shimla, Ooty) are cooler than places at sea level (Delhi,
Chennai).
3. Pressure & Winds –
o Monsoon winds are the main factor.
o India experiences seasonal reversal of winds.
4. Distance from the Sea (Continentality) –
o Coastal areas (Mumbai, Chennai) have moderate climate.
o Interior areas (Delhi, Kanpur) have extreme climate.
5. Ocean Currents & Relief –
o Example: Warm ocean current (Gulf Stream), cold current (Labrador).
o Himalayas act as a barrier → protect India from cold winds from Central Asia.
3. Indian Monsoon
India’s climate is described as “Monsoon type”.
Word Monsoon → derived from Arabic word Mausim meaning season.
Monsoons are seasonal winds → reversal of wind direction according to season.
4. Seasons in India (as per Indian Meteorological
Department – IMD)
1. Cold Weather Season (Winter) – December to February
o North-East Monsoon winds.
o Cool, dry season.
o Rainfall in Tamil Nadu coast due to retreating monsoon.
2. Hot Weather Season (Summer) – March to May
o High temperature in North India.
o Local hot winds: ‘Loo’ in North India.
o Kalbaisakhi (West Bengal, Assam) – thunderstorms with rain.
3. Advancing Monsoon (Rainy Season) – June to September
o SW Monsoon winds bring heavy rainfall.
o Arabian Sea branch + Bay of Bengal branch.
o Example: Mawsynram (Meghalaya) → highest rainfall in the world.
4. Retreating Monsoon (Transition Season) – October to November
o Monsoon winds retreat.
o “October Heat” – hot and humid climate.
o Cyclones occur in Bay of Bengal.
5. Distribution of Rainfall in India
Heavy rainfall: North-eastern states, Western coast.
Moderate rainfall: Ganga valley, NE plateau.
Low rainfall: Western Rajasthan, Leh, Gujarat interior.
Very low rainfall: Ladakh, Thar desert.
6. Importance of Monsoon
Lifeline of India’s agriculture.
“Monsoon binds the whole country” – agriculture, economy, festivals, and lifestyle
depend on it.
Class 9 Geography – Climate (Q&A)
2. Answer briefly
(i) Controls affecting climate of India:
Latitude, Altitude, Pressure & Winds, Distance from Sea, Relief, Ocean Currents.
(ii) Why monsoon type of climate?
Due to seasonal reversal of winds caused by differential heating of land and water, India
experiences monsoon type of climate.
(iii) Highest diurnal range of temperature?
North-western India (Thar Desert, Rajasthan) → because of sandy soil, clear skies,
and low humidity → very hot days & very cold nights.
(iv) Winds causing rainfall along Malabar Coast?
South-West Monsoon winds (Arabian Sea branch).
(v) Define Monsoons & Break:
Monsoon: Seasonal reversal of wind direction bringing rainfall.
Break in Monsoon: Rainfall is not continuous → dry intervals occur due to shifting of
monsoon trough.
(vi) Why monsoon unifying bond?
Monsoon influences agriculture, economy, lifestyle, festivals, and cultural practices of
India → thus binds the whole nation.
3. Why does rainfall decrease from east to west in Northern
India?
The Bay of Bengal branch of monsoon moves westward along the Himalayas.
Moisture is gradually lost → eastern areas get more rain, western areas get less.
4. Give reasons
(i) Seasonal reversal of winds → Due to differential heating of land (faster) and ocean (slower).
(ii) Bulk of rainfall in few months → 75% rainfall comes from June–Sept (advancing
monsoon).
(iii) Tamil Nadu coast gets winter rain → North-East monsoon winds pick moisture from Bay
of Bengal and strike TN coast.
(iv) Eastern delta struck by cyclones → Retreating monsoon over Bay of Bengal + low-
pressure systems → cyclones hit Andhra, Odisha, Bengal coasts.
(v) Rajasthan, Gujarat, leeward of Western Ghats drought-prone →
Western Rajasthan & Gujarat = far from monsoon winds.
Leeward of Ghats = rain shadow region.
5. Regional variations in India’s climate
Jammu & Kashmir → below 0°C in winter.
Rajasthan (Thar Desert) → >50°C in summer.
Coastal regions → moderate, equable climate.
Northeast (Mawsynram) → highest rainfall (>1100 cm).
Rajasthan & Ladakh → scanty rainfall (<10 cm).
6. Weather conditions in Cold Season (Dec–Feb)
Days → Cool; Nights → Cold.
North-East Monsoon winds blow.
Rainfall in Tamil Nadu from retreating monsoon.
Western disturbances bring winter rain to North-West India.
Low humidity, clear skies.
7. Characteristics & Effects of Monsoon Rainfall
Characteristics:
Seasonal & uneven distribution.
Breaks and bursts common.
Highly variable (intensity & duration).
Effects:
Agriculture: Major crops depend on timely rainfall.
Economy: Good monsoon = prosperity, Poor monsoon = drought.
Floods/Droughts: Excess → floods; deficit → droughts.
Unifying role: Determines festivals, farming, daily life.
