The seasonal end of the monsoon when rains taper off and dry weather returns. Begins in north India in mid-September and reaches the southern tip by mid-October.
PhenomenaWhat is Monsoon Retreat?
Monsoon retreat — also called monsoon withdrawal — is the end of the southwest monsoon season. It is the reverse of monsoon onset: rains taper, low-level moisture drops, winds shift from southwesterly to northerly/northeasterly, and clear, drier weather returns.
For India and South Asia, the retreat is the transition from the wet season to the post-monsoon and winter seasons. It is just as important to agriculture as the onset, because:
- Late-monsoon rain affects the final maturation of kharif crops (rice, soybean, maize).
- Timely withdrawal allows the rabi (winter crop) sowing window — wheat, mustard, gram — to begin.
- A delayed retreat can damage standing rice crops and delay rabi planting.
- A premature retreat can leave reservoirs and groundwater under-recharged.
The retreat is usually a gradual, multi-week process — not a single date as onset is.
How IMD declares retreat
The India Meteorological Department declares the start of monsoon withdrawal, from extreme north-west India, only after 1 September and on the following criteria:
- Cessation of rainfall over the area for 5 consecutive days.
- Establishment of an anticyclone in the lower troposphere (850 hPa and below).
- Considerable reduction in moisture content, as seen in satellite water-vapour imagery and tephigrams.
Further withdrawal is declared keeping spatial continuity, with reduced moisture and dry weather for 5 days.
For each district, IMD tracks the actual withdrawal date and publishes a daily progress map during September–October.
Withdrawal dates across South Asia
The monsoon withdraws from north to south, opposite to its advance. Average dates:
| Location | Average Withdrawal |
|---|---|
| Western Rajasthan | 17 September |
| Punjab, Haryana | 22 September |
| Delhi NCR | 25 September |
| UP, Bihar | 1 October |
| Madhya Pradesh, Chhattisgarh | 5 October |
| Maharashtra, Odisha | 10 October |
| Karnataka, Telangana | 15 October |
| Tamil Nadu | 15–20 October (replaced by NEM) |
| Kerala | 15–20 October |
Bangladesh: Late September to early October. Pakistan: 10–20 September across the eastern plains.
This whole process — from the start of withdrawal in northwest India (17 Sept) to peninsular completion — takes about 30 days.
What happens during retreat
As the monsoon withdraws:
- The Monsoon Trough (low-pressure belt) shifts southward off the Indian landmass.
- The Tropical Easterly Jet weakens and disappears.
- The Subtropical Jet descends south, beginning to dominate north Indian upper-level flow.
- Sea-surface temperatures in the Bay of Bengal remain warm (28–30°C), making the bay a cyclone factory.
- Northeast monsoon sets in over Tamil Nadu and Sri Lanka — winds reverse to northeasterly, picking up moisture from the Bay.
Delays and anomalies
A delayed monsoon withdrawal has happened in several recent years:
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2010: Withdrawal from west Rajasthan began only on 27 September, nearly 4 weeks behind the normal date of the time (1 September).
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2019: Withdrawal began only on 9 October, more than a month after the normal date of the time (1 September); September rainfall was 152% of the long period average, the highest since 1917.
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2022: Withdrawal delayed; October cyclones overlapped with monsoon rain.
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2002: The monsoon withdrew from most of west Rajasthan on 16 September, against a normal date of 15 September, but it left the entire country only on 25 October, 10 days late.
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2009: Both a stalled advance (8–20 June) and a late retreat (withdrawal began only on 25 September, more than 3 weeks behind the normal date of the time), in a season that brought only 77% of the long period average rainfall.
Climate change and monsoon retreat
Research suggests:
- The monsoon retreat is becoming more erratic, sometimes delayed by 1–2 weeks.
- More intense bursts of rainfall before the retreat (late September–early October cloudbursts).
- Bay of Bengal cyclone season is extending later into the year.
- Western Disturbance arrival in north India is shifting later into November.
Practical implications
For farmers:
- Plan harvest of rice and soybean around expected withdrawal date.
- Watch for “second flush” of rain in late September that can lodge crops.
- Begin rabi land preparation as soon as withdrawal is confirmed.
For travellers:
- Late September to mid-October is a transition window — northern India clears up, Tamil Nadu/Sri Lanka begin their wet season.
- October–November (post-monsoon) is the best travel season for most of India.
For city planners:
- Late-September cloudbursts have caused major urban flooding (Patna 2019).
- Monitor IMD bulletins for unusual rainfall patterns during retreat.
Frequently asked questions
When does the monsoon withdraw from Delhi? Average withdrawal date: 25 September, but since 1961 it has ranged from 3 September (1982, earliest) to 17 October (2013, latest).
Is monsoon retreat the same as the end of rain? No — even after withdrawal, occasional showers can occur. “Withdrawal” means the systematic monsoon circulation has ended; isolated post-monsoon rain is normal.
Why does Tamil Nadu get its main rainfall AFTER the monsoon withdraws? Because Tamil Nadu’s main rainy season is the northeast monsoon (October–December), when winds reverse and bring moisture from the Bay of Bengal. The southwest monsoon barely affects coastal Tamil Nadu — its rain has to cross the Western Ghats and is largely depleted.
Can the monsoon “withdraw” then return? Rare but possible. In 2019, the retreat was so delayed and erratic that several states had renewed rainfall episodes in early October before final withdrawal.
Where can I track monsoon withdrawal for my city? IMD publishes daily withdrawal maps in September–October. Mausam Online shows live and forecast rainfall on every city page — useful for seeing the local end of the wet season. See Delhi, Lucknow, Mumbai, Kolkata, Chennai.