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Key Points at a Glance
- Rajasthan can be divided into 4 rainfall-based climatic zones: Western Desert (<10 cm in the driest core around Jaisalmer), Semi-arid (10-50 cm), Sub-humid (50-100 cm), and Humid (>100 cm in the wettest pockets such as Mount Abu and parts of the southeast). This is the simplest RPSC-friendly framework because it links climate directly with crops, settlement, drought risk, and vegetation.
- Köppen classification assigns 4 major climate zones to Rajasthan: Aw (tropical savanna in the southeast), BSh (hot semi-arid steppe over much of central and western Rajasthan), BWhw (hot desert in the extreme west), and Cwg (humid subtropical monsoon climate in the east). In answers, name the code, the region, and one climatic feature.
- Mount Abu receives about 150 cm annual rainfall and is the highest-rainfall station in Rajasthan; Jaisalmer receives about 10 cm and is the driest district headquarters-level climate example used in Rajasthan geography. This contrast is the clearest way to show the state's extreme climatic gradient.
- Rajasthan's average annual rainfall is about 57 cm, compared with India's roughly 117 cm. Around 75-80% of the state's rainfall is concentrated in the southwest monsoon season, mainly from July to September, so even a short monsoon break can create serious agricultural stress.
- Phalodi in Jodhpur district recorded 51.0°C on May 19, 2016, India's all-time highest officially reported temperature. Use this as the flagship example for Rajasthan's summer heat, especially in answers on continentality and heat waves.
- Western Disturbances bring winter rainfall, locally called Mawat or Mahawat, to northern and western Rajasthan. This rainfall is small in volume but critical for rabi crops such as wheat, mustard, and gram.
- The southwest monsoon reaches Rajasthan through two branches: the Arabian Sea branch, which enters through Gujarat and is weaker over western Rajasthan, and the Bay of Bengal branch, which enters through central India and is more important for southeastern and eastern Rajasthan.
- The Fatehpur-Sikar belt is the coldest winter pocket, often recording sub-zero minimum temperatures, while Churu is famous for recording both severe summer heat and intense winter cold in the same annual cycle. These examples show how desert continentality works in both directions.
- Rajasthan-specific teaching commonly uses 5 seasonal phases: Summer (March-June), Pre-monsoon or Hot Dry (May-June), Southwest Monsoon (July-September), Post-monsoon or Retreating Monsoon (October-November), and Winter (December-February). The extra emphasis on the hot-dry phase is useful because Loo, dust storms, and heat waves are major exam themes.
- Drought frequency is high: Rajasthan faces drought roughly 3 out of every 10 years at the state scale, while western districts can face drought risk in 6-8 out of 10 years. El Niño years are especially important because they often weaken the southwest monsoon.
- The Aravalli Range acts as a climatic divide. The eastern side generally receives 60-100 cm rainfall, while the western leeward side receives less than 50 cm; the Thar expands most strongly where the Aravalli is low, broken, or absent.
- Climate change impacts in Rajasthan include rising mean temperatures, more frequent heat waves, shifts in monsoon onset and withdrawal, higher rainfall variability, and faster desertification pressure in the Thar and semi-arid belts.
- Loo is the hot, dry wind that blows mainly from west to east during May-June, often when temperatures reach 45-50°C. It causes heat stress, heat stroke risk, crop wilting, and rapid soil-moisture loss.
- Annual rainfall variability is extremely high in western Rajasthan, where the coefficient of variation can exceed 40%, compared with about 20% for India as a whole. This is why a place with a low rainfall average can swing between near-flood and drought years.
- Monsoon onset normally reaches southeastern Rajasthan by late June, advances towards northwestern Rajasthan by mid-July, and begins withdrawing from the northwest in September. For RPSC answers, always connect onset, distribution, and withdrawal with crop calendars and drought risk.