2. On the whole India experiences 4
seasons.
1. The cold and dryWinter season/NE
monsoons (December to February)
2. The hot and dry Summer season(
March to May)
3. The Hot and wet Rainy Season/SW
monsoon Season June to September)
4. The period of retreating
monsoon(October and November)
3.
4. The term ‘monsoon’ is derived from the Arabic word
‘mausim’(mausam) which means season.
Thus monsoon winds are the winds which blow from sea to
land in one season and from landmass towards the sea in
the other season.
The climate of south Asia in general and India in particular
is influenced by monsoon.
5. Factors affecting climate of India.
1. The Himalayas.
2. Moderating influence of the sea.
3. Relief features.
4. Prevailing winds/NE monsoon
winds.
5. Altitude.
6. Latitudinal extent.
7. Western disturbance/ Jet Streams.
8. El nino.
6.
7. 1.The Himalayas:
a.They block chilly cold winds blowing
from Arctic Ocean towards India during
winter and save us from them.
b.They also block moisture laden winds
blowing from India to Central Asia.
c.Thus in the absence of the Himalayas
our climate had been hot and dry during
summer and cold and dry during winter.
8.
9.
10. 2.Moderating influence of the Sea:
Arabian sea, Bay of bengal and the
Indian Ocean provide moisture and
climate of coastal areas is modified by
them .There we experience maritime
climate whereas in the interior we
experience Continental type of
climate/extreme climate.
Punjab , Haryana, M.P. U.P. Etc
experiences this extreme climate.
16. Mumbai receives more rainfall than Nasik explain.
Ans: Mumbai lies on the windward side of the Western Ghats
whereas nasik lies on the leeward side.
When the winds are blocked by the Western Ghats, the
windward side gets more rain but when the winds cross the
mountain and go towards the leeward side, their moisture
content decreases and hence that side receives less rain.
17. 1. Summer monsoon
winds bring cover
whole of India and
bring rainfall.
2. NE monsoon winds
blow from land to
sea and hardly bring
any rain.
3. However eastern
coastal region does
receives some
rainfall from them.
3.Impact of
prevailing wind:
18. SW Monsoon winds in Summer and NE
monsoon winds blow during winter
19. Relief features:
Western Ghats,
Himalayas etc. act as
barriers and cause
heavy rainfall to the
windward side.
The amount of rainfall is
comparatively lesser to
the leeward side of the
mountains.
Thus the relief feature is
one of the key factors
that determine the
climate of India.
20.
21. Windward side of theWestern Ghats have thick and
dense forest due to heavy rainfall
26. Rainfall in Nasik is less heavy or less as it
is on leeward side side
27. Latitudinal Position
Tropic of Cancer(231/2N)
passes through the central
part of India.Therefore the
adjacent areas experience
tropical climate.The
regions aboveTOC
experienceTemperate
conditions.The Southern
region of the country
experiences equatorial type
of climate
due to its proximity with
the equator.
28. Altitude:
For every 1000 meter
ascent there is a drop of
6 degree C in
temperature(lapse rate).
Thus the hill stations like
Nainital, Darjeeling, Ooty,
Shimla, Mahabaleshwar
etc. remain cold throughout
the year. However the
places on the places like
Delhi, Jaipur are warmer
than the hill station
30. Upper air circulation:
These are swiftly
blowing winds at a
height of 3 to 5 Kms
above the subtropical
high pressure belt.
Himalayas divide
them into Easterly &
Westerly Jet.
TheWesterly Jet
cause western
disturbances in North-
west India and bring
about winter rainfall.
31.
32. Easterly jet stream is responsible for bringing tropical
depressions over India.
2.They also play important role in rainfall distribution as
they control the ONSET and the DEPARTURE of monsoons
in India.
33.
34.
35. El Nino effect:
The cold Peruvian Current keeps the Pacific
Oceans colder than the Indian Ocean and
hence Low pressure prevails here.
But sometimes a warm El Niño current
appears in the Pacific Ocean in the Pacific
Ocean which causes Trade winds to reverse
their direction and the moisture laden winds
instead of moving towards India, move
towards Peru and thus deprives India of its
share of monsoon.
37. Western disturbance: In the winter
due to the shifting of the pressure
belts, theWesterlies blow from 20 to
50 degree N latitude and India comes
under their influence along with the
influence of the cyclone rising from
the Mediterranean Sea.These winds
bring rain to Jammu Kashmir and
Northern plains of India.
38. Jet streams/ Upper air circulation.
1.These are the air currents which develop in the
upper layer of the atmosphere (3 to 5 km above the
surface).
2. Himalayas block them and divide them into
westerly and easterly jet streams.
3.The westerly jet stream prevail over NW and
bring winter rainfall while the easterly jet streams
steer tropical depression over India.
4.These depressions play imp. role in the
distribution pattern of monsoon rainfall.The
highest rainfall occurs along the track of these
depressions.
44. Features of the Indian Climate:
1. Diversity of climatic conditions. Due to the vastness of the
country and the varied relief features there is not only difference
from season to season but also from region to region.
2. Tropical monsoon type climate due to the dominance of the
monsoon mechanism: There are two monsoons which control
Indian climate and they are SW monsoon winds and NE monsoon
winds which change the direction of winds.
3. Development of tropical depression or cyclones over the Bay of
Bengal: Towards the end of monsoon ( rainy season), cyclones
may originate in the Bay of Bengal and the Andaman Sea which
bring heavy rain to Andhra Pradesh and Orissa. They can cause
devastating floods during retreating monsoon. These cyclones
travel in northwest direction and are weakened along the Arabian
Sea coast in Pakistan.
4. Winter rainfall in specific regions: Punjab and Haryana due to the
Western Disturbance and the Coromandal Coast from the NEMW.
45. Rainfall duringWinter.
The NE monsoon winds blow from land
towards sea in the south and cause about 70
cm rainfall in coastal regions of
TN(Coromandal coast) and that of Andhra
Pradesh causing heavy flood and destroy
crops.They give 3 -4 cm rain to Karnataka.
Westerly depression which originates in the
Mediterranean Sea travels eastward and
causes rainfall of 10 to 15cm in the Himalayas,
Punjab, Haryana and JK which is beneficial to
wheat crop in Punjab and Haryana.
53. The Hot Season:The hot Season lasts from March to May.
(a)Temperature:As the sun’s rays fall vertical overTropic of Cancer,
the temperature
begins to rise.The average temperature is above 30°C, the maximum
temperature rises to
50°C in Barmer (Rajasthan).The daily range of temperature rises in
inland areas.
(b) Pressure andWinds: Intense heat results in the development of
low pressure over
North-West India.A high pressure exists over Indian Ocean. South-
West Monsoons begin
to blow from Sea to land.‘Nor-westers’ and ‘Loo’ blow over Northern
plains.
(c) Rainfall: Some areas receive convectional rainfall.The west coast
also starts receiving
rainfall. Most of the country is dry in title pre-Monsoon period.
54. The Hot Season: The hot Season lasts from March to May.
(a) Temperature: As the sun’s rays fall vertical over Tropic of
Cancer, the temperature
begins to rise. The average temperature is above 30°C, the
maximum temperature rises to
50°C in Barmer (Rajasthan). The daily range of temperature rises
in inland areas.
(b) Pressure and Winds: Intense heat results in the development of
low pressure over
North-West India. A high pressure exists over Indian Ocean.
South-West Monsoons begin
to blow from Sea to land. ‘Norwesters and ‘Loo’ blow over
Northern plains.
(c) Rainfall: Some areas receive convectional rainfall. The west
coast also starts receiving
rainfall. Most of the country is dry in title pre-Monsoon period.
57. Kalbaisakhi
or
Norwester.
These winds are known as
Kalbaisakhi inWB and Assam
and in Punjab and U.P.They are
called as Norwester.
In May hot and dry winds blow
towards Bay of Bengal andWarm
and moist wind blow from Bay
of Bengal towards land.When
these winds collide, it results
into heavy rain with
thunderstorms.
This rain is useful for tea crop in
Assam and for jute and rice in
WB.
However it is dangerous to life
and property.
70. Its a hot, dry and
dusty wind blowing
over the Great
Indian plain during
May and June
At this time temp
rises up to 45 to 50
degree C which
causes sun strokes
in Bihar, U.P.,
Haryana and
Punjab.
LOO
74. Pre monsoon showers:
During summer extreme low pressure is developed
over the interior of India. However, the pressure
over the Arabian Sea is more as water does not get
heated as fast as land.
Thus the moisture laden winds blow in April and
May towards western costal region of India
bringing rain there and it is termed as pre monsoon
showers AS IT ARRIVES BEFORETHE MONSOON
SEASON IN June.
They are termed as mango showers in Maharashtra
and coffee or cherry blossom in Karnataka and
Kerala.
75. Mango showers are pre monsoon
winds in Maharashtra.They are
good for ripening of mangoes.
Cherry blossom/coffee blossom:
These are pre monsoon winds in
Karnataka. In Karnataka they are
called so as they are good for the
cultivation of tea and coffee.
85. The Rainy Season:
SW monsoon winds blow from the sea
towards land from June to September.
They get divided into 2 branches ,
1.The Arabian Sea branch and
2. The Bay of Bengal branch
88. Arabian Sea Branch of SW monsoon winds:
These winds strike the coast of Kerala by the first
week of June. The Western Ghats make them rise
high. Heavy rain(200-250cm)occurs on the
windward slopes of the Western Ghats. While the
leeward side receives only 60cm of rainfall.
The rain shadow area receives still less.
2. Further east Chennai receives 30 to 40 cm of
rains. From South to north Thiruvananthapam
(325cms), Goa(300 cms) & Mumbai gets 200 cms
rains.
3. The Aravalli hills, being parallel to S-W
monsoon winds do not form barrier. Therefore
there is little or no rainfall in Thar desert.
89.
90.
91. WhyThar is a desert region?
The Aravalli hills, being parallel to S-W
monsoon winds do not form barrier.
Therefore
there is little or no rainfall in
theThar desert.
92. Warm and wet rainy
season due to SW
monsoon winds
1.The arrival of monsoon is due to high
pressure belt over the Indian Ocean and
low pressure belt on the Indian sub
continent.
2.The moisture laden winds start blowing
from the ocean towards land .
Sudden approach of these winds is
associated with thunder & lightning.This is
known as the BURST OF MONSOON.
2. SW monsoons blows in 2
branches.
1.The Arabian sea branch and
2.The Bay of Bengal branch.
It gives very little rain to Rajasthan
as
1.It cannot be blocked by the
Aravalli which are low in height
2.They R located in NS direction.
3.Also due to high temp, the wind
does not get saturated .
93. What do you mean by the burst of the
monsoon?
Ans: 1.The arrival of monsoon is due to high
pressure belt over the Indian Ocean and low
pressure belt on the Indian sub continent.
2.The moisture laden winds start blowing
from the ocean towards land .
Sudden approach of these winds is associated
with thunder & lightning. This is known as the
BURST OF MONSOON.
94.
95. SW monsoon winds reaches
Kerala 1st of June.Western Ghats
block them and receives 200cm
rainfall and eastern side(leeward
side) receives about 100 cm.
Mumbai receives 250 cm and
Pune on the other side receives
70 cm and Chennai which is
further east gets 30 cm rainfall.
Why does rainfall decrease
from South to North?
Rainfall decreases from S to
N. due to duration of rainfall
and losing of moisture. for eg.
Thirruvanthpuram receives
325, Goa 300 and Mumbai 250
cm.They reach Delhi by 15th
July.
They meet the Bay of Bengal
branch at the foothills of the
Himalayas.
98. Monsoon in Western Ghats: Winds are blocked by the Sahyadris
and give torrential rain to the coastal region.
99. SW monsoon winds while
blowing over Bay of Bengal
too picks up moisture and
gets deflected by the
ArakanYoma and North
east Hills, Garo, Khansi and
Jaintia
Andaman Nicobar, Sri
Lanka are the first one to
receive rain from them.
They shed more rain on
South od f these hills where
Cherrapunji and
Mawsynram are located.
Bay of Bengal
Branch
100. 2.The remaining rain of this branch is deflected
towards west along the Himalayas towards
Rajasthan and on the way its moisture content goes
on decreasing. This current finally merges with Arabian
Branch at the Himalayan foothills .
101.
102.
103. Temperate cyclones. Tropical cyclones.
1 They are of frontal
origin and largely
develop over the
landmasses around the
Mediterranean Sea
They are of the thermal
origin and develop over the
Tropical Seas like the Bay
of Bengal and the
Andaman Sea.
2 They bring light
showers in NW India
for several weeks. Also
bring snowfall in the
higher altitude.
They cause heavy rainfall,
strong winds and high
waves in the eastern coastal
areas. They are of short
duration lasting for few
minutes to hours but are
potentially very destructive.
108. WhyThar is a Desert?
Arabian Sea branch of SW monsoon
winds runs parallel to the Aravalli and
hence unable to shade much rain there.
The Bay of Bengal Branch of SW monsoon
winds after shedding moisture, reaches
the Aravallis and gets blocked by it.
Hence the leeward side of Rajasthan
which is the western part does not
receive rain from it. Hence the desert is
formed here.
112. Distribution of Rainfall
1. It is not even.
Areas of heavy rainfall(200cm):Assam, Arunachal P,W.B,
Southern slope of eastern Himalayas andWestern Coastal
region.
Areas of moderate heavy rainfall(100 to 200cm): Middle
GangaValley,Western Ghats, M.P, Orissa and eastern
Maharashtra.
Areas of Moderate rainfall(50 to 100 cm): Upper ganga
Valley, Eastern Rajasthan and Punjab, Karnataka, AnP and
TN.
Areas of scanty rainfall: (Less than 50 cm); Northen parts of
Kashmir,West Rajasthan, Punjab,rainshadow region of the
Deccan Plateau .
113. Characteristics of SW monsoon winds:
1. Except for TN they give rainfall to entire India for the period of
2 to 4 months and this rainfall is unevenly distributed.
2. Monsoon is erratic in nature which is evident from the fact that
floods cause damage to life and proper in N. Indian Plains and
droughts in NW parts of Rajasthan.
3. The most important aspect of this rainfall is that its nature is
OROGRAPHIC caused mainly by the Himalayas and the Sahyadris.
4. Due to local variations in temperature, Tropical depression
originated at the head of Bay of Bengal and causes
CONVENTIONAL rainfall.
5. Economy of India mainly depends on agriculture which is
influenced by the Monsoon. 64% of the agriculture depends on it.
6. One more feature of monsoon is that it is IRREGULAR in
nature.
7. Variability of monsoon in space and time causes havoc in
agriculture of India.
118. Retreating monsoon. ( October and November)
1.After September, the temperature begin to
decrease and thus High pressure begins to form in
Northern part of India somewhere in October
month but that time southern India is still warm
and has Low Pressure.
2.Thus the SW monsoon winds cannot reach the
Northern part due to the presence of HP but can
reach southern India thus they begin to get
retreated from north to India .This retreating is not
a 180 degree turn.
119. Retreating monsoon. ( October and November)
1.After September, the temperature begin to
decrease and thus High pressure begins to form in
Northern part of India somewhere in October
month but that time southern India is still warm
and has Low Pressure.
2.Thus the SW monsoon winds cannot reach the
Northern part due to the presence of HP but can
reach southern India thus they begin to get
retreated from north to India .This retreating is not
a 180 degree turn.
3.After October, the HP develops in Central India
and thus SW winds can reach only to south India
where its still low pressure.
120. 4. By the end of November, the
high pressure develops in South
India also and finally the SW
monsoon winds stop coming to
India.
5.These winds bring rain mainly
to south India.
121. October Heat.
1.The months of October-November form a
period of transition from hot-rainy season to
dry winter conditions.
2.The retreat of the monsoon is marked by
clear skies and rise in temperature.While day
temperatures are high, nights are cool and
pleasant.
3.The land is still moist. Owing to the
conditions of high temperature and humidity,
the weather becomes oppressive during the
day. It is commonly known as 'October heat’
129. It starts in early December and lasts upto February.
Northern regions experience more cold as they are away from
the Equator.The closeness to the equator and moderating
influence of the sea results into Southern India having warm
climate.
Gangetic plains varies from 2.5 to 17.5⁰C .In the south it remains
above 21.In mountainous region it drops below 0⁰C.
During this time coastal regions receive rain due to NE monsoon
winds whereas J&K, Punjab, Haryana get rain fromWesterly
depression originating from the Mediterranenan sea.
Some part of N.India get cyclonic rainfall due to western
disturbance.
Remaining part of the country has cloudless, rainless, cool
pleasant season.
130. Characteristics features of the Cold Season
1. Its the beginning of NE monsoon winds and their
direction is influenced by the local high pressure
conditions.
2.Winter rain is another feature which is helpful to rabi
crops.
3.The special feature isVARIATION in temp in the north
and the south.The temp decreases as one moves from the
south to the north.
4. Rain inTN brought by the NE monsoon benefit rice and
wheat in Punjab are benefitted by theWestern Disturbance(
Temperate cyclone).
5.The climate is pleasant, fine, cool and with great variation
in the range of the temperature.
131.
132. Temp.Condition in the south in winter
1. Isotherm( A line joining the places of
equal temperature on the map ) of 20 degree
that runs parallel to theTropic of Cancer
divides India climatically.
2. In the south of this Isotherm the
temperature always remains above 21
degree and in the extreme south it is above
25 degree.
3. In the coastal region temp remains above 21
degree throughout the year on account of the
moderating effect of the sea.
133. Winter in North India
Temp.Condition in the North Indian Plains in winter
155. Characteristics of
monsoons in
Indian
1. Monsoons are
erratic in
nature.
2. They are
unevenly spread
& are sporadic.
3. They are
orographic.
4. They bring rain
in Summer
165. 1 They carry immense moistures from the
Arabian Sea, bay of Bengal and I. Ocean.
They carry moisture from the Bay of bengal
2 They blow from SW to NE direction from
sea to land
They blow from NE to SW direction from
land to sea
3 They cause widespread rain in most part
of India.
They bring rain to the Coromandal coast
4 They are active from June to September They are active from November to February
166. Climate data.
1.To calculate the annual rainfall , add the rainfall of all the
months and give the proper unit.
2.Annual range of temperature means the difference
between the maximum and minimum temperature.After
calculating it, give correct unit.
3. If the difference is about 10 to 15 degree Celsius, then the
place is located near the sea shore. Such places are said to
have equabl or maritime climate climate.
4. If the range of temperature is more than 15 degrees , then
the place is in the interior( Away from the sea)Such places
have extreme or continental climate.
5. If a place receives the rain in winter then the place must
be in Coromandal coast or in Punjab and Haryana.
167.
168. 1. Annual range of temperature at B= Max temp.-min. temp= 30-
24.4= 5.6 degree C.
2.Annual rainfall at A =Total of rainfall of all the months=
0.1+0.1+0.5+1.5+2.7+11.4+16.7+9+13.4+9+2.7+0. 3= 67.4 cm
3. Station B is on the windward side because it receives more rain.
169. This place has the lower range temperature because it must be
located near the sea and has the moderation effect of the sea and thus
has equable climate
170. Station B has lower temperature as it is at higher altitude. Greater the
altitude, lower is the temperature.
C.Annual rainfall= Sum of rainfall of all the months= 0.4 +0.3+ 1.1
+…..+ 0.3= 21. 8 cm.
Annual range at B= 17.1 degree C
Annual rainfall at A= Sum of rainfall of all months= 131.5 cm
171. .The annual range of the temperature is 9.3 and it is very small
because the place must be located near the sea and experiencing the
moderating effect of the sea.
2. Station B as it is at higher altitude and the temperature decreases
with increasing altitude.
3.Annual rainfall= Sum of rainfall of all the months= 22.8 cm
Annual range: Diff between Max – Min temp.
172.
173. 1. Annual rainfall= Sum of rainfall of all the months= 68.4 cm.
2. Annual range = MaxTemp- Min.Temp= 33.1-23.1= 10 degree C.
3. October to November retreating monsoon winds bring rain and
from December to February the rainfall is due to NE monsoon
winds.
4. Suggest the name of the place
Ans: Chennai.
174.
175. Stati
ons
JJ F M A M J J A S O N D
T in
C( A
)
21 29.3 30 30.1 33.2 31 29.8 28.7 29.7 29.9 26.5 23.2
Rain
in
Cm
(A)
34 27.6 1.2 - - - - 12.5 2 - 33.5 29
T in
C (B)
13.2 19.3 29 32.4 34.5 32.5 31.2 31 29.9 28 26.6 19.2
Rain
in
cm(B)
19.3
cm
23.3 - - - - - - 8.5 23.4 21.6
1. When does the placeA mainly receives its rain?(Season).
2. Calculate the annual range of temperature atA. max temp-MinTemp=
3. When does the Station B gets its rain?
4. Calculate the annual range of temperature at B. Max temp- MinTemp
5. Which winds bring rainfall toA and B respectively..
6. Name the probable names of the stations.A
7. Probable name of place B
Climate Data
176. Stati
ons
J F M A M J J A S O N D
T in
C( A
)
21 29.3 30 30.1 33.2 31 29.8 28.7 29.7 29.9 26.5 23.2
Rain
in
Cm
(A)
34 27.6 1.2 - - - - 12.5 2 - 33.5 29
T in
C (B)
13.2 19.3 29 32.4 34.5 32.5 31.2 31 29.9 28 26.6 19.2
Rain
in
cm(B)
19.3
cm
23.3 - - - - - - 8.5 23.4 21.6
1. When does the placeA mainly receives its rain?(Season). InWinter from Nov to February.
2. Calculate the annual range of temperature atA. max temp-MinTemp= 33.2-21=12.2 D C
3. When does the Station B gets its rain? ( Season).(Winter
4. Calculate the annual range of temperature at B. Max temp – Min temp= 34.5-13.2=21.3 DC
5. Which winds bring rainfall toA and B respectively.A: NE monsoon winds and B:Western Disturbance.
6. Name the probable names of the stations.A is Chennai ,Tuticorin, Puducherry as annula range of temp is
less than 15 degrees.
Probable name of place B is Chandigarh, Bhatinda,Amritsar, Jalandhar as the annual range is more than 15
Climate Data
177. If the range of temperature is less than 15 degree
Celsius, then the place has equable climate due
to moderating effect of the sea.
If the range of temperature is less more 15
degree Celsius, then the place has extreme
climate as it is located away from the
moderating effect of the sea.
178. SEASONS TEMPERATURE & AIR PRESSURE SOURCES OF RAINFALL AREAS AFFECTED
SUMMER
(March to May)
High temperature over land. Highest
temperature over the N & NW states.
Low pressure over the Northern Plains.
High pressure in the surrounding seas.
Norwesters – local
thunderstorms
Northern States
Kalbaisakhi– local
thunderstorms
Assam andWest Bengal
(benefits growing of
jute and rice)
Mango showers– local
thunderstorms
Kerala andTamil Nadu
(benefits growing of
coffee)
Loo (hot dry wind) Northern States
MONSOON
(June to
September)
High temperature over land. Highest
temperature over the N & NW states.
Low pressure over the Northern Plains.
High pressure in the surrounding seas.
SW MonsoonWinds (SW to
NE) – sea to land (on shore)
Maximum rainfall –
western slopes of
Western Ghats and NE
States.
Minimum rainfall –
Rajasthan and J & K.
RETREATING
MONSOON
(October –
November)
Temperature in the northern part of
India decreases. Low Pressure over the
Northern Plains is eliminated.
October Heat over the peninsular India.
Tropical Cyclones over Bay of
Bengal
Eastern coastal states of
India. Causes
destruction.
WINTER
(December to
February)
Low temperature over land. Lowest
temperature over the N & NW states.
High pressure over the Northern Plains.
Low pressure in the surrounding seas.
Western Disturbances
(temperate cyclones)
J&K, Haryana, Punjab,
U.P. Benefits growing
of wheat and barley
NE MonsoonWinds (NE to
SW) – Land to sea (off shore)
CoastalTamil Nadu
