RAS question
The 'October heat' phenomenon in Rajasthan occurs due to:
Correct answer: (B) Retreating monsoon causing high humidity and temperature.
In Rajasthan, October heat occurs during the retreating monsoon because still-warm conditions combine with high humidity to create oppressive weather.
Explanation
NCERT explains that October and November are the months of the retreating monsoon: by late September the southwest monsoon weakens, and it retreats from western Rajasthan by the first week of September. This season is marked by clear skies and a rise in temperature, while the land remains moist. The combination matters: warm air alone is not the full cause, because the lingering moisture raises humidity. High temperature plus humidity makes the weather feel oppressive, which NCERT identifies as October heat. In Rajasthan, retreating monsoon conditions leave humidity in the air while temperatures are still warm, producing the uncomfortable heat associated with October.
Why the other options are wrong
- (A) Direct sunlight may keep temperatures high, but it does not account for the high humidity and moist land conditions that define October heat during the retreating monsoon.
- (C) Volcanic activity is unrelated to the monsoon-season mechanism and is not part of the explanation for October heat in Rajasthan.
- (D) Desert winds explain hot, dry conditions such as the Loo, whereas October heat depends on retreating monsoon humidity combining with warm temperatures.
Concept
This tests the seasonal cycle of the Indian monsoon, especially the transition from the southwest monsoon to retreating monsoon conditions. It recurs in RAS because Rajasthan’s climate questions often hinge on linking a named weather phenomenon to its seasonal mechanism.