The correct option is 1 and 3 only.
Explanation
The months of October and November constitute the season of the Retreating Monsoon. During this transition period, the low-pressure trough over the northern plains weakens and is replaced by a high-pressure system, leading to the withdrawal of the Southwest Monsoon winds.
Statement-wise Analysis:
- Statement 1 is Correct: With the withdrawal of the monsoon, the skies clear up and the humidity levels eventually drop. Consequently, the weather in North India becomes dry. While high temperatures and residual humidity cause October Heat initially, the season is defined by the cessation of the wet spell in the north.
- Statement 2 is Incorrect: The retreating monsoon winds pick up moisture from the Bay of Bengal and bring rainfall primarily to the eastern part of the Peninsula (specifically the Coromandel Coast and Tamil Nadu). The western part of the Peninsula receives the bulk of its rainfall during the advancing Southwest Monsoon season, not the retreating season.
- Statement 3 is Correct: As the apparent movement of the sun shifts towards the south, temperatures in the northern plains start to decrease. The mercury begins to fall rapidly in the second half of October, marking the onset of winter conditions in North India.
Key Takeaway:
The Retreating Monsoon is characterized by clear skies and dry conditions in North India, a rapid drop in temperature starting late October, and rainfall concentrated along the eastern coast of the Peninsula.