Monsoon Withdrawal 2026: IMD Retreating Monsoon Mechanism and El Nino Link for Exams

Quick Answer: What Is Monsoon Withdrawal 2026 and Why It Matters for Exams

Monsoon withdrawal is the process by which the India Meteorological Department (IMD) declares the end of the southwest monsoon over different parts of the country, beginning from west Rajasthan around 17 September and completing over the entire country by around 15 October. The IMD uses fixed, science-based criteria (no rainfall for five days, establishment of an anticyclone, and reduced moisture seen in satellite imagery). In 2026, as in recent years, ocean conditions such as El Nino/La Nina in the Pacific influence both monsoon strength and withdrawal timing. Every element of this topic — dates, criteria, El Nino, northeast monsoon — is a proven source of UPSC, SSC, Banking and CLAT questions.

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What Is the Retreating Monsoon? Definition and Seasonal Timing

The retreating monsoon, also called the reversing monsoon or northeast monsoon, refers to the gradual withdrawal of the southwest monsoon winds from the Indian subcontinent between September and December. As the sun apparently moves southward after the summer solstice, the low-pressure system over northwest India weakens, the Inter-Tropical Convergence Zone (ITCZ) shifts south, and moisture-laden southwest winds are replaced by dry continental winds blowing from land to sea.

The standard exam timeline is:

• Mid-September (around 17 September): withdrawal begins from extreme west Rajasthan and parts of Kutch in Gujarat.
• By end of September: withdrawal from most of northwest India, including Punjab, Haryana, Delhi and west Uttar Pradesh.
• First fortnight of October: withdrawal advances into central India and the northern peninsula.
• Around 15 October: withdrawal from most of the country; the extreme southeastern peninsula (Tamil Nadu coast) sees the transition to the northeast monsoon rains of October–December.

The period of withdrawal, roughly September to November, is popularly called the season of retreating monsoon or “october heat” season over northern India.

IMD Withdrawal Criteria: The Science Behind the Declaration

Since 2006, the IMD declares withdrawal of the southwest monsoon from a region only when all of the following synoptic conditions are met:

1. Absence of rainfall over the region for five consecutive days.
2. Establishment of an anticyclone in the lower troposphere (around 850 hPa) — roughly 1.5 km above sea level — indicating dry, subsiding air.
3. Sharp reduction in moisture content as seen in satellite water vapour imagery, showing dryness in the middle and lower troposphere.
4. Persistence of these conditions, confirming the monsoon circulation has genuinely weakened over the region.

These objective criteria ensure withdrawal is not declared merely because of a break in rainfall. Aspirants should remember the number 850 hPa and the five-day no-rainfall rule — both are common MCQ hooks. Details are published on the official IMD monsoon pages at mausam.imd.gov.in.

Stages of Monsoon Withdrawal Across India

The withdrawal follows a clear southward and southeastward progression, opposite to the onset:

1. Stage 1 – Extreme west Rajasthan and Kutch: around 17 September.
2. Stage 2 – Northwest India: Punjab, Haryana, Delhi, Uttarakhand, west Uttar Pradesh, Jammu — by late September.
3. Stage 3 – Central India and Gujarat: Madhya Pradesh, Chhattisgarh, Odisha, Maharashtra, Telangana — first week to mid-October.
4. Stage 4 – Interior peninsula and northeast India: by around 15 October, including Vidarbha, Andhra Pradesh, and the northeastern states.
5. Stage 5 – Extreme southeastern peninsula: the final withdrawal merges with the onset of the northeast monsoon rains over Tamil Nadu, coastal Andhra, Kerala and south interior Karnataka.

A simple memory hook: onset and withdrawal both begin from Kerala/Rajasthan respectively, but withdrawal is the mirror image of onset in direction.

Retreating Monsoon Weather: Why Tamil Nadu Gets Rain in October–December

During October–December, winds blow from the land (northeast) towards the sea. As these dry continental winds pass over the Bay of Bengal, they pick up moisture and strike the Coromandel Coast (Tamil Nadu) and coastal Andhra Pradesh, where the Eastern Ghats force orographic lifting. Key exam points:

• Tamil Nadu receives about 48% of its annual rainfall from the northeast monsoon, which is why Chennai’s wettest months are October–December.
• The windward side of the Western Ghats gets rain in the southwest monsoon; Tamil Nadu, lying in the rain shadow during June–September, compensates during the retreating monsoon.
• October heat: clear skies and high humidity over northern India after withdrawal cause oppressive heat, locally called “October heat.”
• Tropical cyclones: the retreat season coincides with peak cyclonic activity in the Bay of Bengal (October–December), as warm sea surface temperatures (above 26.5°C) and low wind shear favour cyclogenesis, affecting Odisha, Andhra Pradesh and Tamil Nadu coasts.

El Nino and Its Effect on Monsoon Withdrawal and Strength

El Nino is the abnormal warming of sea surface temperatures (SSTs) over the central and eastern equatorial Pacific Ocean. Its effects on the Indian monsoon work through these mechanisms:

• Warm Pacific SSTs shift convection eastward from the Indonesian region, weakening the Walker circulation (the east–west atmospheric circulation over the Pacific).
• This weakens the southwest monsoon circulation and typically brings below-normal all-India rainfall — historically, about 60% of El Nino years have been drought years in India.
• El Nino years often show a delayed onset, long breaks, and delayed or erratic withdrawal, because the monsoon trough and cross-equatorial flow remain disturbed.
• El Nino years are also associated with suppressed Bay of Bengal cyclone activity during the monsoon season but sometimes enhanced post-monsoon storms over the Arabian Sea region, as noted in research cited by the Ministry of Earth Sciences (PIB).

For 2026: the IMD’s operational position, as issued in its seasonal forecasts and updated ENSO bulletins on mausam.imd.gov.in and press releases on PIB, should be quoted as the authoritative source. The IMD consistently states that ENSO (El Nino/La Nina) is one of several factors influencing monsoon strength, alongside the Indian Ocean Dipole (IOD), Madden–Julian Oscillation (MJO) and mid-latitude weather systems; its impact on withdrawal timing varies year to year. Candidates should always cite the latest IMD statement rather than assuming a fixed outcome.

Difference Between Southwest and Northeast Monsoon: Exam Comparison Table

Climatic Regions and Retreating Monsoon: Geography Fundamentals

This topic connects directly to NCERT Class 11 Fundamentals of Physical Geography (Chapter: Climate) and covers:

• Seasonal reversal of winds: differential heating of land and sea reverses pressure gradients between summer (thermal low over Asia) and winter (high pressure/cold Siberian anticyclone).
• ITCZ shift: the monsoon trough (ITCZ) lies over the Ganga plain in July and shifts south of the equator in winter, driving the reversal.
• Jet streams: the Subtropical Westerly Jet shifts south of the Himalayas in winter (bringing western disturbances), while the Tropical Easterly Jet (linked to Tibetan Plateau heating) strengthens the southwest monsoon.
• Tibetan plateau heating: summer heating of the plateau acts as an elevated heat source, intensifying the monsoon circulation; its cooling in autumn aids withdrawal.
• Climatic region link: the Coromandel Coast’s “rainfall in October–December” regime, and the semi-arid/monsoon regimes elsewhere, are classified in Koppen-based regionalisations used in Indian geography syllabi.

2026 Withdrawal News: Key Headlines and Data Points to Remember

For current-affairs accuracy, always anchor answers to official announcements:

• The normal (long-period) withdrawal dates issued by IMD: 17 September from west Rajasthan; 15 October for the entire country.
• IMD press releases on withdrawal milestones and seasonal rainfall (as % of the long-period average of ~87 cm) are published via PIB and mausam.imd.gov.in — quote the exact date and percentage given in the release of the day.
• Track the ENSO bulletin (IMD’s monthly El Nino/La Nina update) for the 2026 season, and the IOD status, since both are cited in IMD’s seasonal outlooks.
• Recent years show withdrawal has often been delayed by one to two weeks against normal dates, which itself becomes a headline data point for exams.

Note: Since 2026-specific dates are announced progressively during the season, verify the exact day of withdrawal declarations from the IMD release before writing them in an exam.

Previous Year Questions (PYQs) on Indian Monsoon

• UPSC Prelims (2012): “The seasonal reversal of winds is the typical characteristic of — (a) Equatorial climate (b) Mediterranean climate (c) Monsoon climate (d) All of the above.” Answer: (c) Monsoon climate.
• UPSC Prelims: Questions on the normal date of withdrawal of the southwest monsoon from extreme west Rajasthan (17 September) and on Tamil Nadu’s northeast monsoon rainfall regime have appeared repeatedly in one form or another.
• SSC CGL: “Which state receives most rainfall from the northeast monsoon?” — Answer: Tamil Nadu.
• SSC/Banking GA: “El Nino is associated with the warming of which ocean?” — Answer: The Pacific Ocean (central and eastern equatorial Pacific).

Rapid Revision: One-Page Fact Sheet for Exam Day

• Withdrawal begins: west Rajasthan, ~17 September; complete over India: ~15 October.
• IMD criteria (2006): 5 consecutive dry days + anticyclone at 850 hPa + dryness in water vapour imagery + reduced moisture.
• Retreating monsoon = northeast monsoon; winds blow land to sea.
• Tamil Nadu gets ~48% of annual rainfall in October–December.
• October heat: hot, humid conditions over north India after withdrawal.
• Bay of Bengal cyclones peak in October–December.
• El Nino: warm central/eastern Pacific SSTs → weak Walker circulation → weaker monsoon; ~60% of El Nino years are Indian drought years.
• Drivers of reversal: differential land–sea heating, ITCZ shift, Tibetan Plateau heating, jet streams.
• Southwest monsoon = ~75% of India’s annual rainfall.

Practice MCQs on Monsoon Withdrawal

Q1. The IMD declares monsoon withdrawal from a region when there has been an absence of rainfall for how many consecutive days?
(a) 3 (b) 5 (c) 7 (d) 10
Answer: (b) 5

Q2. The normal date of commencement of southwest monsoon withdrawal is:
(a) 1 September from Kerala (b) 17 September from west Rajasthan (c) 15 October from Punjab (d) 1 October from Gujarat
Answer: (b) 17 September from west Rajasthan

Q3. Which of the following states receives the bulk of its rainfall during the retreating monsoon?
(a) Kerala (b) Punjab (c) Tamil Nadu (d) Assam
Answer: (c) Tamil Nadu

Q4. El Nino weakens the Indian monsoon primarily by:
(a) Cooling the Arabian Sea (b) Weakening the Walker circulation due to warm eastern Pacific SSTs (c) Strengthening the ITCZ over the Ganga plain (d) Increasing Tibetan Plateau snowfall in summer
Answer: (b) Weakening the Walker circulation

Q5. As per IMD criteria, the anticyclone signalling withdrawal is identified at which atmospheric level?
(a) 500 hPa (b) 200 hPa (c) 850 hPa (d) Sea level only
Answer: (c) 850 hPa

Frequently Asked Questions

Q: When does the monsoon usually withdraw from India?

Withdrawal of the southwest monsoon begins from west Rajasthan around 17 September and is normally completed over the entire country by around 15 October, as per IMD’s normal withdrawal dates.

Q: Does El Nino delay monsoon withdrawal?

El Nino can weaken monsoon circulation, and El Nino years have often seen delayed or erratic withdrawal — but the effect varies each year. For 2026, cite the IMD’s latest ENSO bulletin and seasonal outlook (mausam.imd.gov.in / PIB) as its stated position; IMD treats ENSO as one of several influencing factors, not the sole determinant.

Q: What is the northeast monsoon?

It is the October–December wind system blowing from land to sea, which picks up moisture over the Bay of Bengal and brings rain mainly to Tamil Nadu, coastal Andhra Pradesh, Rayalaseema and south interior Karnataka.

Q: What are IMD’s withdrawal criteria?

No rainfall for 5 consecutive days, establishment of an anticyclone at 850 hPa, dryness in satellite water vapour imagery, and a marked reduction in atmospheric moisture.

Q: Is monsoon withdrawal important for competitive exams?

Yes. It appears in UPSC Prelims (geography), SSC CGL general awareness, Banking GA, CLAT GK and current-affairs sections, often combined with El Nino and IMD announcements.

Sources: India Meteorological Department (mausam.imd.gov.in), Press Information Bureau (pib.gov.in), NCERT Class 11 Fundamentals of Physical Geography.