Climatic regions of India

India, being a vast country does not fit into any one zone. Situated roughly between 8° N and 37° N
Latitude, it occupies a large area of South Asia.

The climate of India defies easy generalization, comprising a wide range of weather conditions across a
large geographic scale and varied topography. Analyzed according to the Köppen system, India hosts six
major climatic subtypes, ranging from desert in the west, to alpine tundra and glaciers in the north, to
humid tropical regions supporting rain forests in the southwest and the island territories. Many regions
have starkly different micro climates. The nation has four seasons: winter (January and February),
summer (March to May), a monsoon (rainy) season (June to September), and a post-monsoon period
(October to December).

India's unique geography and geology strongly influence its climate; this is particularly true of the
Himalayas in the north and the Thar Desert in the northwest. The Himalayas act as a barrier to the frigid
katabatic winds flowing down from Central Asia. Thus, North India is kept warm or only mildly cold during
winter; in summer, the same phenomenon makes India relatively hot. Although the Tropic of Cancer—the
boundary between the tropics and subtropics—passes through the middle of India, the whole country is
considered to be tropical.

As in much of the tropics, monsoonal and other weather conditions in India are unstable: major droughts,
floods, cyclones and other natural disasters are sporadic, but have killed or displaced millions.

India has a large variation in climate from region to region, due to its vast size. India experiences climate
from four major climate groups. These can be further subdivided into seven climatic types.

Tropical rainy climatic group

The regions belonging to this group experience persistent high temperatures which normally do not go
below 18°C even in the coolest month. There are two climatic types which fall under this group.

Tropical monsoon rain forest

The west coastal lowlands, the Western Ghats, and southern parts of Assam have this climate type. It is
characterized by high temperatures throughout the year, even in the hills. The rainfall here is seasonal,
but heavy and is above 78 in a year. Most of the rain is received in the period from May to November, and
is adequate for the growth of vegetation during the entire year. December to March are the dry months
with very little rainfall. The heavy rain is responsible for the tropical wet forests in these regions, which
consists of a large number of species of animals.

Tropical wet and dry climate

Most of the plateau of peninsular India enjoys this climate, except a semi-arid tract to the east of the
Western Ghats. Winter and early summer are long dry periods with temperature above 18°C. Summer is
very hot and the temperatures in the interior low level areas can go above 45°C during May. The rainy
season is from June to September and the annual rainfall is between 75 and 150 cm. Only Tamil Nadu
receives rainfall during the winter months of October to December.

Dry climate group

This group consists of regions where the rate of evaporation of water is higher than the rate of moisture
received through precipitation. It is subdivided into three climate types.

Tropical semi-arid steppe climate

A long stretch of land situated to the south of Tropic of Cancer and east of the western ghats and the
Cardamom Hills experiences this climate. It includes Karnataka, interior Tamil Nadu, western Andhra
Pradesh and central Maharashtra. This region is a famine prone zone with very unreliable rainfall which
varies between 40 to 75 cm annually. Towards the north of Krishna River the summer monsoon is
responsible for most of the rainfall, while to the south of the river rainfall also occurs in the months of
October and November. The coldest month is December but even in this month the temperature remains
between 20°C and 24°C. The months of March to May are hot and dry with mean monthly temperatures
of around 32°C. The vegetation mostly comprises grasses with a few scattered trees due to the rainfall.
Hence this area is not very well suited for permanent agriculture.

Tropical and sub-tropical desert

Most of western Rajasthan falls under this climate type characterized by scanty rainfall. Cloud bursts are
largely responsible for the all the rainfall seen in this region which is less than 30 cm. These happen when
the monsoon winds penetrate this region in the months of July, August and September. The rainfall is
very erratic and a few regions might not see rainfall for a couple of years. The summer months of May
and June are very hot with mean monthly temperatures in the region of 35°C and highs which can
sometimes reach 50°C. During winters the temperatures can drop below freezing in some areas due to
cold wave. There is a large diurnal range of about 14°C during summer which becomes higher by a few
more degrees during winter. This extreme climate makes this a sparsely populated region of India.

Tropical and sub-tropical steppe

The region towards the east of the tropical desert running from Punjab and Haryana to Kathiawar
experiences this climate type. This climate is a transitional climate falling between tropical desert and
humid sub-tropical, with temperatures which are less extreme than the desert climate. The annual rainfall
is between 30 to 65 cm but is very unreliable and happens mostly during the summer monsoon season.
Maximum temperatures during summer can rise to 40°C. The vegetation mostly comprises short coarse
grass. Some crops like jowar and bajra are also cultivated.

Humid sub-tropical climate group

The temperature during the coldest months in regions experiencing this climate falls between 18 and 0°C.
It has one climatic subdivision in India.

Humid sub-tropical with dry winters

The foothills of the Himalayas, Punjab-Haryana plain adjacent to the Himalayas, Rajasthan east of the
Aravalli range, Uttar Pradesh, Bihar and northern part of West Bengal and Assam experience this climate.
The rainfall is received mostly in the summer and is about 65 cm in the west and increases to 250 cm
annually to the east and near the Himalayas. The winters are mainly dry due to the land derived winter
winds which blow down the lowlands of north India towards the Bay of Bengal. The summers are hot and
temperatures can reach 46°C in the lowlands. May and June are the hottest months. Winter months are
mostly dry with feeble winds. Frost occurs for a few weeks in winter. The difference in rainfall between the
east and the west gives rise to a wide difference in the natural vegetation and crops.

Mountain climate
In the Himalayan mountains the temperature falls by 0.6°C for every 100 m rise in altitude and this gives
rise to a variety of climates from nearly tropical in the foothills to tundra type above the snow line. One
can also observe sharp contrast between temperatures of the sunny and shady slopes, high diurnal range
of temperature, inversion of temperature, and variability of rainfall based on altitude.

The northern side of the western Himalayas also known as the trans-Himalayan belt is arid, cold and
generally wind swept. The vegetation is sparse and stunted as rainfall is scanty and the winters are
severely cold. Most of the rainfall is in the form of snow during late winter and spring months. The area to
the south of the great Himalayan range is protected from cold winds coming from interior of Asia during
winter. The leeward side of the mountains receives less rain while the well exposed slopes get heavy
rainfall. The places situated between 1070 and 2290 m altitudes receive the heaviest rainfall and the
rainfall decreases rapidly above 2290m. The great Himalayan range witnesses heavy snowfall during
winter months of December to February at altitudes above 1500m. The diurnal range of temperature is
also high.

The states of Jammu and Kashmir, Himachal Pradesh, Uttarakhand and Sikkim experience this kind of
weather.

Seasons

The India Meteorological Department (IMD) designates four official seasons.

Cycle of season

Though divided into different climatic zones, India seems to be unified by primarily four seasons- Winter, Summer,
Advancing Monsoon and Retreating Monsoon.

Winter: December to February is the wintertime in almost all of India. At this time of the year, days are cold with
average temperature of10-15 �C, but it can drop down to below 0 �C in some higher ranges of northern India.
Normally winters are dry in northern India. Temperatures rise as one proceeds towards the equator, peaking
around 20–25 °C (68–77 °F) in mainland India's southeast.In Southern part, the temperature difference is not
so marked due to moderating effect of Indian Ocean, Bay of Bengal and Arabian Sea.

Summer: March, April, May and June are the summer months in India. It is a time period when rays of the sun fall
vertically on Indian subcontinent. The average temperature is around 32 c but in western region the maximum
temperature can be far above the average. Hot wind, known, as 'Loo' is the marked feature of summers in northern
India. In western and southern regions, the hottest month is April; for northern regions, May is the hottest
month. Temperatures average around 32–40 °C (90–104 °F) in most of the interior.

Advancing Monsoon: It is the time period when India gets major part of its share of rain. Months of June, July,
August and September form the core of Advancing Monsoon in almost all parts of country. The monsoon approaches
with moisture laden winds, this sudden approach is marked with violent thunderstorms and lightening, known as
'break' of the monsoon.

Retreating Monsoon: This season starts, when monsoon after drenching all of India, begins to retreat. With the
month of September, rainfall began to decrease and as we approach November, the monsoon is completely gone
from major part of India, except for Tamil Nadu and some other southern states, which also receive rain from Western
Disturbance.

In recent times, this cycle of season has been disturbed due to uncontrolled industrialization and other developmental
activities resulting in drastic changes in climate. This has lead to climatic disasters such as Drought, Landslides
Floods and Global Warming. The unchecked cutting down of trees indirectly leads to landslide and drought. Annual
Floods have become part of life in many regions of India. It results in large-scale loss of life and property.
The Himalayan states, being more temperate, experience an additional two seasons: autumn and spring.
Traditionally, Indians note six seasons, each about two months long. These are the spring (Sanskrit:
vasanta), summer (grīṣma), monsoon season (varṣā), early autumn (śarada), late autumn (hemanta), and
winter (śiśira). These are based on the astronomical division of the twelve months into six parts. The
ancient Hindu calendar also reflects these seasons in its arrangement of months.
Jaisalmer, Hot and Dry

No. of Clear
Mean Monthly Mean Monthly Mean Monthly
Days in a Places
Temp. (°C) R.H. (%) Preciptation
month
Rajasthan,
Hot & dry >30 <55 <5 >20 Ahemadabad,
Gujarat

Very high daytime temperatures, with very little precipitation and a short and mild winter season
characterize this climate. Another important characteristic is a high diurnal temperature variation. You can
be boiling during the day and cold at night. This is due to the rapid radiative heat loss from the ground or
the building to the clear night sky.

The desert town of Jaisalmer deals with this by building homes that abut against each other, with the
inner rooms opening towards small courtyards and the front rooms opening through screened openings
towards narrow shaded streets. This pattern minimizes the exposure of building surfaces to the outside.

The buildings are of heavy mass and the windows small, because of which the indoor temperature
changes very little through the day or night, staying close to a more comfortable daily mean temperature.

In summers, even though the day is hot, nights are cool, and people spend time out on the roof terrace.
Because humidity is low, if water was available, cooling by evaporation of water would be an easy and
effective way of obtaining thermal comfort.

jaisalmer
jaisalmer haveli elevation

jaisalmer haveli plans

jaisalmer haveli plans

 jaisalmer section

jaisalmer site plan

Leh, Cold and Sunny

No. of clear
Mean Monthly Mean Monthly Mean Monthly
days in a Places
Temp. (°C) R.H. (%) Precipitation
month
Cold & cloudy <25 <55 <5 >20 Ladakh

Leh in Ladakh is a "mountain desert." There is very little precipitation and the temperatures vary greatly
between the day and night and also from summer to winter. The traditional Ladhaki settlement is usually
built on steep slopes facing southward. This allows good insolation during the day.

Heavy walls (mud) and a well insulated roof (timber & mud) dampen the variations of indoor
temperatures.

The use of glass and nowadays, trombe- wall is very successful as heat can be stored in the building
mass during the day, to stay warm indoors at night.
Padamanabhapuram Palace, Trivandrum, Warm and Humid

No. of clear
Mean Monthly Mean Monthly Mean Monthly
days in a Places
Temp. (°C) R.H. (%) Precipitation
month
Trivandrum, Coastal
Warm & humid >30 >5
Areas/ North East.

High humidity, strong sun, glare from the sky and horizon characterize this climate. There are long
monsoon periods with heavy rain. But the breezes, especially in coastal areas, can alleviate discomfort
considerably.

The Padmanabhapuram Palace in Trivandrum, responds to the climate with steep sloping high tiled roofs,
with deep eaves. The sides are open to the breeze, and air ventilates up through the porous tile roofs,
ensuring that the indoor temperature does not build up.
Using open slatted or perforated timber screens on sides of verandahs cuts out glare, ensures privacy but
allows the breeze flow across the rooms. Walls are white to reflect the sun, and often completely shaded
by the verandahs.

For a cluster of buildings, an openness of planning, to allow the natural breeze to flow through them is of
paramount importance.

Sauni Village, U.P., Cold and Cloudy

Mean Monthly Mean Monthly Mean Monthly No. of clear Places

 days in a
Temp. (°C) R.H. (%) Precipitation
month
J&K, Himachal, NW
Cold & cloudy <25 >55 >5 <20
UP, Niligiri

Winters are prolonged and summers are short in this climate. There is also a fair amount of precipitation-
snow or rain, often spread across the year.

The traditional homes and villages of the sub - Himalayan region are built on hill slopes that would receive
a fair amount of sunshine. The lower floor is occupied by cattle and used for storage. The upper floor
which is away from cold and damp ground has the living rooms. The cooking area is a part of it, in order
to benefit from the heat generated by it. Low timber ceiling provide insulation and conserve the warmth.
Windows face the sun.

House Elevation

House Section
Rang Mahal, Red Fort, Delhi, Composite

New Delhi has a Composite climate. It has a very hot and dry summer, followed by a humid season with
monsoon rains. With the departure of the monsoon it gradually becomes comfortable in autumn, followed
by a short winter with the cloudy and wet as well as sunny periods. Before the summer returns there is a
comfortable but short spring season.

The Rang Mahal at the Red Fort royal palace has spaces suitable for every season. Rooms have thick
walls and small openings for summer days and winter nights. Verandahs are for evenings and mornings.
There is a screened balcony that will cut out the sun but enjoy the monsoon breeze during the humid
season.

Additionally, there is water stream flowing through the middle and the screens and awnings that can be
raised or lowered to modulate the light, provide shade, or insulate against the heat or cold.

Exterior RangMahal RedFort

Interiors Rang Mahal RedFort

 Plan Rang Mahal RedFort

Bangalore, Moderate

No. of clear
Mean Monthly Mean Monthly Mean Monthly
days in a Places
Temp. (°C) R.H. (%) Precipitation
month
Moderate 25-30 <75 <5 <20 Bangalore, Deccan

This is a climate which is generally comfortable; neither too hot, nor too cold, and where all of us should
be staying! All you need to do is be shaded and insulated from direct sun, let in a little breeze when you
feel stuffy or warm: and shut the window if it is chilly or wear some light woolens.

In Banglore, the ideal comfortable house is built of heavy walls with high ceiling rooms, with windows that
you can shut and open, surrounded by a shade giving verandah.

High ceilings reduce the effect of heat that would radiate down from the roof which would get hot under
the sun. This will also allow the warm air to rise and escape through ventilators, high up in the walls.
Ground Floor Plan
External View

Spaces