Climate – Characteristics and Their Classification

In Rajasthan Geography, Rajasthan’s climate, marked by extreme heat and low rainfall, ranges from Jaisalmer’s arid Thar Desert to Udaipur’s semi-arid zones. Classified as arid, semi-arid, and sub-humid, it shapes agriculture and settlement.

Previous Year Question

General Introduction

• Climate is the long term phenomena taking place in the atmosphere surrounding earth,it  is decided on the basis of average 30 years weather conditions. 

Characteristics of Rajasthan climate

• Region wise diversity in climate is seen.
• Subtropical Climate condition is found in Rajasthan।
• Average climate is arid and semi-arid
• Rainfall – Avg 58 cm annually
  • About 90% rainfall received in summer months (June-July) during southwest monsoon।
  • Very less 3% from western disturbance।
  • Irregular and uncertain (1000cm over southeastern parts to 14 cm over extreme northwestern parts)।
  • Scarce- drought famines are common।

• Temperature – extreme temperature during summer(30-40°C) and winters (10-12°C)
  • Daily temperature variations are also high(Jaisalmer); sand gets easily heated up and cooling is also fast
• Wind direction change with change in seasons
• Diverse physical reliefs also put great impact on climate and local humidity
• Winds from western plateau of Baluchistan also affect climate making it dry, less humid and consequently resulting in less rainfall.

 Factors affecting climate of Rajasthan

• Latitudinal location- 23°3’N to 30°12’N।
• Subtropical location.
• Higher temperature variations.
• Distance from sea
  • Continental climate- warm and dry
• Height from seafloor and reliefs
  • Most regions are less than 370m height from sea level, therefore high temperature and less humidity
  • Hadoti plateau and Aravalli range are high, therefore high humidity and high rainfall
  • 60% part of state is desert (sandy soil); high daily and seasonal temperature difference; summer (loo) winter (too cold winds)
  • Location of Aravalli range (southwest to north east)
  • Parallel to southwest monsoon winds from Arabian sea (no obstruction therefore pass without rainfall)
  • Blocks Bay of Bengal branch therefore rainfall in eastern and southeastern parts
  • Western parts being rain shadow region, doesn’t receive adequate rainfall
• Natural vegetation
  • Affects climate and is affected in return
  • Affects temperature, humidity
  • Most areas of Rajasthan have less and scattered vegetation, therefore rainfall is less 

Seasonal Classification of climate

There are four types of Seasons found in Rajasthan

1. Summer Season (March – June)
2. Rainy Season (June – September)
3. Autumn Season (October – November)
4. Winter Season (December – Febuary)

Summer Season

• With the start of summer solstice-more vertical sun rays fall over the state,resulting in high temperature therefore low air pressure
• Average temperature 38°C (western districts 45°-48°C)
• Local hot wind flow called as LOO (due to advection flow of wind-horizontal)
• Sandstorms also occur very commonly (due to convectional flow of wind-vertical)
• Bhabhulya (due to spiral or cyclonic winds)
• Least humidity is found during this season

Rainy Season/Monsoon

• Arrival 25^th June (@banswara, Dungarpur)
• Retreat 30^th September
• Average annual rainfall 57.5cms (india-125cms)
• Monsoon rains contribute 90% of Rajasthan’s annual rainfall
• Southwest monsoon is divided into two branches- Arabian sea branch and Bay of Bengal branch. 
• Arabian sea branch again divides into 3 branches- western ghat, Chota Nagpur, Himachal branch (causes first rain in Rajasthan which is very low).
• Bay of Bengal branch divides into two branches- eastern Himalaya branch and Western Great northern-plain branch (brings maximum rainfall in Rajasthan )
• EL-NINO- is a hot oceanic current occurring during the last week of December, which weakens monsoon in India and Rajasthan also(also known as Ocean fever / Child of Christ)
• LA-NINA-is cold oceanic current occurring during the last week of December, which makes monsoon strong for India and Rajasthan also (also known as younger sister of EL – Nino)

Autumn season

• Retreating of Monsoon (withdrawal of monsoon)
• Kartik heat (increase in temperature when the Monsoon is retreating)
• Oct-nov months
• Minimum daily temperature difference

Winter season

• High pressure and low temperature
• December to March
• Cold winds from Himalayas

Mavath

• winter rainfall during month of December to march, brought by western disturbances from Mediterranean sea(western jet stream flowing at low latitudes); called as golden drops(blessing for rabi crops) ;
• contributes 10% of Rajasthan’s annual rainfall 
• also called as temperate monsoon/winter monsoon/ Mediterranean monsoon/north west monsoon.

Climate Classification

General Classification of Climate

Rajasthan is divided into five parts on the basis of Rainfall & Temperature –

Climatic region	ARID	SEMI ARID	SUB HUMID	HUMID	VERY HUMID
Temperature (summer)	35-40°C	32-36°C	28-34°C	32-35°C	30-34°C
Temperature (winter)	12-16°C	10-17°C	12-18°C	14-17°C	12-15°C
Rainfall	0-20cms	20-40cms	40-60cms	60-80cms	80-150cms
Vegetation	Xerophytes and thorny bushes	Steppe type, bushes, khejari, rohida, leelan & sevan grasses	Neem, babool, mango, amla, wheat, barley, gram,mustard	Dense vegetation, rose, neem, mango, rice, jowar, sugarcane	Savannah type sagwan, seesam, cotton
Physical division	North-Western Desert	North-Western Desert	Aravalli	Eastern Plain	Hadoti Plateau & Mahi Besin
miscellaneous	Sand dunes Sand storms and Loo	Inland drainageSalt water lakes
Expansion Areas	Jaisalmer, Bikaner, Northern Barmer, Phalodi, Northwestern Jodhpur, Western Nagaur, Western Churu, Southern Sri Ganganagar	Sri Ganganagar, Hanumangarh, Sikar, Jhunjhunu, Churu, Nagaur, Didwana-Kuchaman, Jodhpur, Pali, Jalore	Khairthal-Tijara, Kotputli-Behror, Jaipur, Dausa, Alwar, Tonk, Ajmer, Beawar, Bhilwara, Sirohi	Bharatpur, Deeg, Sawai Madhopur, Karauli, Dholpur, Bundi, Rajsamand, Chittorgarh	Jhalawar, Kota, Baran, Pratapgarh, Banswara, Dungarpur, Mount Abu, Southern Udaipur, Southern Salumber, Southern Baran

Individual Classification 

By Koppen 

 According to Koppen Climate of Rajasthan is divided into four parts based on Vegetation, Temperature and Rainfall. 

CLIMATIC REGION	Aw	BWhw	BShw	Cwg
Climate –	Tropical Humid / Very Humid	Arid Desert	Semi Arid	Sub-Tropical , Sub – Humid
Vegetation	Savanna Type	Xerophytes and Thorny Vegetation	Steppe Grassland	Dry Deciduous
Area	Vagad (Banswara, Dungarpur, Pratapgarh), Hadoti (Southern Kota, Baran, Jhalawar), Mount Abu, Partial Chittorgarh	Jaisalmer, Bikaner, Churu, Sriganganagar, Hanumangarh.	Luni Basin, Nagaur, Shekhawati, Ghaggar Basin	Alwar, Bharatpur, Deeg, Karoli, Dholpur, Ajmer, Bhilwara, Bundi, Chittorgarh, Dausa, Rajsamand, Tonk, Swai-Madhopur, Udaipur, Jaipur, Gangapur City
Mics	maximum Vegetation density	Minimum Rainfall and Thorny Vegetation	largest climate zone	Maximum Population density,Maximum agricultural production

By Thornthwaite

 Rajasthan’s climate is divided into four parts based on the Temperature, Evaporation and Rainfall. 

CLIMATIC REGION	CA’w	DA’w	DB’w	EA’d
Climate	Humid	Semi-arid	Arid and Semi-arid	Dry arid
Area	Banswara, Dungarpur, Pratapgarh, Jhalawar, Baran and South Kota and Partial Chittorgarh.	Alwar, Bharatpur, Karauli, Dholpur, Ajmer, Bundi, Bhilwara, Chittorgarh, Dausa, Jaipur, Nagaur and Pali	Bikaner, Churu, Ganganagar, Hanumangarh.	Jaisalmer, Barmer, Balotra, West Jodhpur, Bikaner and Phalodi.
Mics		largest climatic region

By Trewartha

Rajasthan’s climate is divided into four parts based on Rainfall.

Climatic Regions of Rajasthan

Climate Type	Annual Rainfall (cm)	Major Districts
Aw – Tropical Humid Climate	80-100 cm	Banswara, Salumber, Eastern Udaipur, Dungarpur, Pratapgarh, Chittorgarh, Baran, Jhalawar, Southern Kota
BSh – Tropical Semi-Arid Climate	40-60 cm	Western Udaipur, Hanumangarh, Rajsamand, Sirohi, Jalore, Southeastern Barmer, Jodhpur, Pali, Ajmer, Nagaur, Churu, Jhunjhunu, Sikar, Sri Ganganagar, Bikaner, Western Bhilwara
BWh – Tropical Desert Climate	10-20 cm	Jaisalmer, Southwestern Bikaner, Northwestern Barmer
Caw – Subtropical Climate	50-80 cm (Winter Rain due to Cyclones)	Kota, Bundi, Baran, Tonk, Sawai Madhopur, Karauli, Bharatpur, Dholpur, Alwar, Dausa

Climate – Characteristics and Their Classification / Climate – Characteristics and Their Classification / Climate – Characteristics and Their Classification / Climate – Characteristics and Their Classification / Climate – Characteristics and Their Classification / Climate – Characteristics and Their Classification