Topic 84: Climate of Raj. – Characteristics and

Study Material

Paper Paper II

Unit 3

1. Rajasthan has 4 climatic zones by rainfall: Western Desert (<10 cm), Semi-arid (10–50 cm), Sub-humid (50–100 cm), Humid (>100 cm).
2. Köpppen classification assigns 4 zones to Rajasthan: Aw (tropical savanna — southeast), BSh (hot semi-arid steppe), BWhw (hot desert), Cwg (humid subtropical — east).
3. Mt. Abu receives ~150 cm annual rainfall — highest in Rajasthan; Jaisalmer receives ~10 cm — lowest in India for a district headquarters.
4. State average annual rainfall: ~57 cm (compared to India's ~117 cm). 75–80% of rainfall concentrated in the SW monsoon season (July–September).
5. Phalodi (Jodhpur district) recorded India's all-time highest temperature of 51°C on May 19, 2016.
6. Western Disturbances (पश्चिमी विक्षोभ) bring winter rainfall (Mawat/Mahawat) to northern and western Rajasthan, critical for rabi crops (wheat, mustard).
7. SW monsoon reaches Rajasthan via two branches: Arabian Sea branch (enters via Gujarat, weaker) and Bay of Bengal branch (enters via Vindhyas, dominant).
8. Fatehpur-Sikar belt is the coldest zone in winter, recording sub-zero temperatures; Churu holds the record for both extremes in the same year.
9. Rajasthan has 5 distinct seasons: Summer (March–June), Pre-monsoon/Hot Dry (May–June), SW Monsoon (July–September), Post-monsoon/Retreating (October–November), Winter (December–February).
10. Drought frequency: Rajasthan experiences drought in approximately 3 out of every 10 years; western districts face drought risk in 6–8 out of 10 years. El Niño years strongly correlate with drought.
11. Aravalli range acts as a climatic divide: windward (eastern) side receives 60–100 cm rainfall; leeward (western) side receives <50 cm — the Thar extends where the Aravalli is low or absent.
12. Climate change impacts: Rising mean temperatures (+0.5°C over 50 years in Rajasthan), increased heat wave frequency, shifting monsoon onset, and accelerating desertification of the Thar.
13. Loo (लू) is the hot dry wind blowing from west to east in May–June, with temperatures reaching 45–50°C; causes heat strokes and crop damage.
14. Annual rainfall variability in Rajasthan is extremely high: co-efficient of variation (CV) exceeds 40% in the desert zone (compared to ~20% for India as a whole).
15. Monsoon onset in Rajasthan: Bay of Bengal branch reaches southeastern Rajasthan by late June; northwestern Rajasthan by mid-July; withdrawal begins in September from northwest. / मानसून आगमन: दक्षिण-पूर्वी राजस्थान में जून के अंत तक; उत्तर-पश्चिम में जुलाई मध्य तक; सितंबर में उत्तर-पश्चिम से वापसी शुरू। ---

Key facts

Rajasthan has 4 climatic zones by rainfall: Western Desert (<10 cm), Semi-arid (10–50 cm), Sub-humid (50–100 cm), Humid (>100 cm).
Köpppen classification assigns 4 zones to Rajasthan: Aw (tropical savanna
Mt. Abu receives ~150 cm annual rainfall — highest in Rajasthan; Jaisalmer receives ~10 cm — lowest in India for a district headquarters.
State average annual rainfall: ~57 cm (compared to India's ~117 cm). 75–80% of rainfall concentrated in the SW monsoon season (July–September).
Phalodi (Jodhpur district) recorded India's all-time highest temperature of 51°C on May 19, 2016.

Key Points at a Glance

1
Rajasthan has 4 climatic zones by rainfall: Western Desert (<10 cm), Semi-arid (10–50 cm), Sub-humid (50–100 cm), Humid (>100 cm).
2
Köpppen classification assigns 4 zones to Rajasthan: Aw (tropical savanna — southeast), BSh (hot semi-arid steppe), BWhw (hot desert), Cwg (humid subtropical — east).
3
Mt. Abu receives ~150 cm annual rainfall — highest in Rajasthan; Jaisalmer receives ~10 cm — lowest in India for a district headquarters.
4
State average annual rainfall: ~57 cm (compared to India's ~117 cm). 75–80% of rainfall concentrated in the SW monsoon season (July–September).
5
Phalodi (Jodhpur district) recorded India's all-time highest temperature of 51°C on May 19, 2016.
6
Western Disturbances (पश्चिमी विक्षोभ) bring winter rainfall (Mawat/Mahawat) to northern and western Rajasthan, critical for rabi crops (wheat, mustard).
7
SW monsoon reaches Rajasthan via two branches: Arabian Sea branch (enters via Gujarat, weaker) and Bay of Bengal branch (enters via Vindhyas, dominant).
8
Fatehpur-Sikar belt is the coldest zone in winter, recording sub-zero temperatures; Churu holds the record for both extremes in the same year.
9
Rajasthan has 5 distinct seasons: Summer (March–June), Pre-monsoon/Hot Dry (May–June), SW Monsoon (July–September), Post-monsoon/Retreating (October–November), Winter (December–February).
10
Drought frequency: Rajasthan experiences drought in approximately 3 out of every 10 years; western districts face drought risk in 6–8 out of 10 years. El Niño years strongly correlate with drought.
11
Aravalli range acts as a climatic divide: windward (eastern) side receives 60–100 cm rainfall; leeward (western) side receives <50 cm — the Thar extends where the Aravalli is low or absent.
12
Climate change impacts: Rising mean temperatures (+0.5°C over 50 years in Rajasthan), increased heat wave frequency, shifting monsoon onset, and accelerating desertification of the Thar.
13
Loo (लू) is the hot dry wind blowing from west to east in May–June, with temperatures reaching 45–50°C; causes heat strokes and crop damage.
14
Annual rainfall variability in Rajasthan is extremely high: co-efficient of variation (CV) exceeds 40% in the desert zone (compared to ~20% for India as a whole).
15
Monsoon onset in Rajasthan: Bay of Bengal branch reaches southeastern Rajasthan by late June; northwestern Rajasthan by mid-July; withdrawal begins in September from northwest. / मानसून आगमन: दक्षिण-पूर्वी राजस्थान में जून के अंत तक; उत्तर-पश्चिम में जुलाई मध्य तक; सितंबर में उत्तर-पश्चिम से वापसी शुरू।

Introduction and Syllabus Scope

The RPSC 2026 syllabus for Paper II, Unit 3 under Earth Science requires a Rajasthan-first understanding of climatic characteristics, climate classification, and the factors that control climate across the state. This topic demands three-layered knowledge: climatic characteristics such as temperature, rainfall, humidity, and winds; climate classification through the Köppen system as applied to Rajasthan and the regional zone-based Indian classification; and controlling factors such as latitude, the Aravalli barrier, distance from the sea, relief, and monsoon tracks. The examiner's focus is always Rajasthan-first because the state's extreme climatic contrasts, from the hyper-arid Thar to the sub-humid southeast, make it one of the most climatically diverse states in India.

Tier 3 PYQ status (2/5 exams, average 2.0 marks per year) indicates moderate but consistent examination presence. RPSC has asked narrow 5-mark questions such as defining Loo or naming coldest and hottest places, and analytical 10-mark questions such as explaining the factors controlling Rajasthan's climate or the characteristics of the monsoon. The 2026 syllabus revision also elevates climate change as a sub-theme, making it more likely to appear through heat waves, drought, desertification, or Aravalli-linked ecological questions.

Scope boundaries: Topic #83 on physiography provides the landform base: the Aravalli, the Thar Desert, the eastern plains, and the plateau regions that explain rainfall distribution. Topic #85 on natural vegetation is directly determined by climatic zones, so a student must understand this chapter to answer vegetation questions. Topic #87 on agriculture depends heavily on monsoon timing, Western Disturbances, drought frequency, and rainfall variability. Do not re-explain physiography or vegetation details here; cross-reference them when needed.

This chapter covers climatic controls, Köppen classification, regional climate zones, seasonal patterns, temperature and rainfall distribution, Western Disturbances, drought and famine, and climate change impacts on Rajasthan. A good Mains answer should combine a classification table, a west-to-east rainfall explanation, one temperature record, one drought point, and a Rajasthan-specific current affairs link.

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PREDICTED Predicted RAS Questions

Based on PYQ trends and 2026 syllabus analysis

1 5M What are Western Disturbances? Explain their origin and agricultural significance for Rajasthan. 5 marks · 50 words

Model Answer

Western Disturbances are extratropical cyclones originating over the Mediterranean Sea, carried eastward by mid-latitude westerly jet streams. They bring winter rainfall (Mawat/Mahawat, 1–5 cm per event, 4–8 events per season) to northern Rajasthan — Ganganagar, Sikar, Jhunjhunu. This moisture is critical for rabi crops: wheat, mustard, and gram. Without Mawat, rabi yields decline sharply.

~50 words • 5 marks