Monsoon begins withdrawing from west Rajasthan with 43% of India's area rain-deficient
The monsoon is leaving on time, but 15% short. What decides when it 'withdraws', and what comes next?
Published 20 September 2026. Written by Pratidin from the reports linked at the end; every fact checked by a separate review before publishing. How we work
The India Meteorological Department (IMD) announced that the southwest monsoon withdrew from some parts of West Rajasthan on 19 September 2026, against the normal date of 17 September. The line of withdrawal passed through 27.0°N/68.0°E, Ramgarh, Mohangarh, Phalodi, Khajuwala and 29.5°N/71.5°E. IMD said conditions were favourable for further withdrawal from more parts of Rajasthan, Punjab, and Saurashtra and Kutch over the next three to four days. The line of withdrawal is the boundary IMD draws on the map to show the area from which the monsoon has retreated; it moves south and east over the following weeks.
The season has been weak. The Indian Express reported that all-India rainfall up to 19 September stood at 695.6 mm, 15% below normal, and that nearly 43% of the country's geographical area was rain-deficient. Rainfall was below normal in June, August and September, while July was only about 1% above normal. Meghalaya, Andhra Pradesh, Arunachal Pradesh and Bihar were among the worst affected. At the same time, IMD said a low-pressure area was likely to form over the north Andaman Sea on the evening of 19 September, intensify into a depression over the east-central Bay of Bengal on 21 September and into a deep depression over the west-central Bay of Bengal on 22 September, and reach near the south Odisha-north Andhra Pradesh coasts around the morning of 23 September, with isolated extremely heavy rain likely over Odisha on 23 and 24 September.
In 2020 IMD revised the normal dates of the monsoon: onset over Kerala on 1 June, coverage of the whole country by 8 July, the start of withdrawal from northwest India on 17 September and complete withdrawal by 15 October. Withdrawal is declared only after 1 September, when rain stops over an area for several consecutive days, an anticyclone sets in over the lower atmosphere and moisture falls sharply. After the southwest monsoon leaves, the northeast monsoon (October to December) brings much of the year's rain to Tamil Nadu and nearby areas. A deficit at this stage matters for reservoir storage, groundwater recharge and soil moisture for the rabi (winter) crop, while late-season depressions can still cause floods in eastern and central India.
Prelims facts
- The southwest monsoon began withdrawing from parts of West Rajasthan on 19 September 2026; the normal date is 17 September.
- All-India rainfall up to 19 September 2026 was 695.6 mm, 15% below normal, with nearly 43% of the country's area deficient.
- IMD's normal dates (revised in 2020): onset over Kerala 1 June, whole country by 8 July, withdrawal from 17 September, complete withdrawal by 15 October.
- A low-pressure area over the north Andaman Sea was forecast to become a deep depression and approach the south Odisha-north Andhra Pradesh coasts around 23 September.
- The northeast monsoon (October to December) is the main rainy season for Tamil Nadu.
Quick recall
- When did the southwest monsoon begin withdrawing in 2026?
- 19 September 2026, from parts of West Rajasthan.
- What is the normal date for the start of monsoon withdrawal from northwest India?
- 17 September (IMD's revised normal, 2020).
- What was all-India rainfall up to 19 September 2026?
- 695.6 mm, 15% below normal.
- What share of India's area was rain-deficient by 19 September 2026?
- Nearly 43%.
- What is the normal onset date of the monsoon over Kerala?
- 1 June.
- By when does the monsoon normally cover the whole country?
- 8 July.
- By when does the monsoon normally withdraw completely?
- 15 October.
- Which State gets much of its annual rain from the northeast monsoon?
- Tamil Nadu.
Prelims practice question
With reference to the Indian monsoon, consider the following statements:
1. As per IMD's revised normal dates, the southwest monsoon begins to withdraw from northwest India around 17 September.
2. The southwest monsoon covers the entire country by the normal date of 1 June.
Which of the statements given above is/are correct?
- 1 only
- 2 only
- Both 1 and 2
- Neither 1 nor 2
Show answer
Answer: (a) 1 only. Statement 1 is correct: since the 2020 revision, the normal date for the start of withdrawal from northwest India is 17 September. Statement 2 is incorrect: 1 June is the normal onset date over Kerala; the monsoon covers the whole country by about 8 July.
Use this in UPSC Mains: previous-year questions
Recurring theme: Mechanism and variability of the Indian monsoon and its effects on agriculture
- How to use this
Illustrates the monsoon's seasonal rhythm, wind reversal and dependence of crops and water on its timing.
- IMD's normal dates (revised 2020): onset over Kerala 1 June, whole country by 8 July, withdrawal from 17 September, complete withdrawal by 15 October.
- As the heat low over northwest India weakens, winds reverse and the northeast monsoon (October to December) brings much of Tamil Nadu's rain.
- In 2026 all-India rainfall to 19 September was 15% below normal; note that deficits hurt rabi soil moisture, reservoirs and food prices.
- How to use this
Gives a current example of an erratic monsoon season; it is not attributed to land-use change, so present it only as evidence of variability.
- All-India rainfall to 19 September 2026 was 695.6 mm, 15% below normal, with nearly 43% of the country's area rain-deficient.
- Rainfall was below normal in June, August and September, while July was only about 1% above normal.
- Withdrawal began from West Rajasthan on 19 September against the normal 17 September, while IMD forecast isolated extremely heavy rain over Odisha from a late Bay of Bengal depression.
Monsoon forecasts depend on drivers such as the Indian Ocean Dipole and El Niño, which shape seasons like 2026.
Mains practice question
Explain the process of the retreat of the southwest monsoon. How does a deficient monsoon season affect Indian agriculture and water security? (150 words)
Model answer
The southwest monsoon began withdrawing from West Rajasthan on 19 September 2026, with all-India rainfall 15% below normal.
Process of retreat
- Weakening heat low: as the Sun moves south, the low pressure over northwest India weakens.
- IMD criteria: after 1 September, rain stops for several days, an anticyclone forms in the lower atmosphere and moisture drops.
- Direction: withdrawal moves from northwest India south and east, normally complete by 15 October.
- Transition: winds reverse and the northeast monsoon brings rain to Tamil Nadu from October.
Effects of a deficient season
- Kharif output: rainfed crops such as pulses and oilseeds suffer.
- Rabi prospects: low soil moisture and reservoir storage hurt winter sowing.
- Water security: weaker groundwater recharge and urban supply stress.
- Economy: food inflation and lower rural demand.
Better storage, micro-irrigation and crop diversification can reduce India's exposure to monsoon swings.
The basics
Why this matters
About three quarters of India's annual rain comes in the four months of the southwest monsoon, June to September. So the day it starts leaving is watched closely: it marks the end of the main sowing and recharge season. In 2026 the Retreating monsoon set in close to schedule, but the season was about 15% short of the Long Period Average.
How the monsoon arrives and leaves
In summer, the land of northwest India and Pakistan heats up and forms a low-pressure area. Moist winds from the Indian Ocean are drawn towards it: that is the southwest monsoon. When the Sun moves south after the September equinox, this low weakens, high pressure builds over the northwest and the winds begin to reverse.
- 1Monsoon reaches Kerala
- 2Covers the whole country
- 3Retreats from northwest India
- 4Leaves the country; winds reverse
- 5Rains over Tamil Nadu and nearby areas
How IMD declares withdrawal
IMD does not declare withdrawal before 1 September. It looks for three signs over an area: rain stops for several consecutive days, an anticyclone (a high-pressure system with outward-spiralling winds) forms in the lower atmosphere, and moisture drops sharply on satellite images. It then draws a line of withdrawal on the map. On 19 September 2026 this line ran through Ramgarh, Mohangarh, Phalodi and Khajuwala in West Rajasthan.
Reading the deficit
IMD calls an area's rainfall 'deficient' when it is 20% to 59% below normal, and 'normal' when it is within 19% either way. For the country as a whole, a season below 90% of the Long Period Average is called deficient. June, August and September 2026 were below normal; only July was marginally above.
Rain can still come
Withdrawal from the northwest does not end rain everywhere. Systems forming over the Bay of Bengal keep bringing heavy rain to the east. In 2026 IMD forecast a low-pressure area to grow into a deep depression and approach the south Odisha-north Andhra Pradesh coasts around 23 September: see Low-pressure systems in the Bay of Bengal. Later, the Northeast monsoon takes over in the south.
Go deeper
In one line: The southwest monsoon began to withdraw from West Rajasthan on 19 September 2026, two days after its normal date, leaving about 43% of India's area rain-deficient.
Why it matters for UPSC
Monsoon mechanics are a GS1 geography staple, and its performance feeds GS3 questions on agriculture, water and food inflation. Prelims often tests normal dates, IMD categories and the sequence of weather systems.
The core idea
The monsoon comes when a summer low forms over northwest India and leaves when that low weakens. IMD tracks the Retreating monsoon with a line of withdrawal. The season's total is judged against the Long Period Average. Even after withdrawal starts, Low-pressure systems in the Bay of Bengal can bring heavy rain to the east, and the Northeast monsoon then brings rain to Tamil Nadu.
Numbers and dates to remember
- Withdrawal began: 19 September 2026 (normal 17 September).
- Withdrawal line: Ramgarh, Mohangarh, Phalodi, Khajuwala.
- Rainfall to 19 September: 695.6 mm, 15% below normal; 43% of area deficient.
- Normal dates: Kerala 1 June; whole country 8 July; complete withdrawal 15 October.
- Low-pressure area forecast to near south Odisha-north Andhra Pradesh coasts around 23 September.
Where to go next
- Retreating monsoon: how and why the monsoon leaves.
- Long Period Average: the benchmark for a normal season.
- Low-pressure systems in the Bay of Bengal: from low to cyclone.
- Northeast monsoon: the winter rains of the south.
Go deeper: how should India read a 15% shortfall?
Why it worries. Rainfall at 85% of normal so far is below the 90% mark that IMD uses for a 'deficient' country-wide season, and the spread matters as much as the total: 43% of the area in deficit means many districts lost rain at key times. Rainfed kharif crops, reservoirs and groundwater recharge all suffer, and low soil moisture can hurt rabi sowing.
Why it may not be a disaster. Irrigation now covers a large part of the sown area, reservoirs carry some storage from earlier years, and late systems like the forecast Bay of Bengal depression can still add rain in the east. The Northeast monsoon can also make up deficits in the south.
Timing versus quantity. The Retreating monsoon started only two days after its normal date, so the season's length was normal; the problem was weak rain within it. This is why the Long Period Average total, the monthly distribution and the district-wise spread must be read together.
Hazards do not end with the season. Low-pressure systems in the Bay of Bengal often form in September and October and can intensify into depressions or cyclones, bringing extremely heavy rain to Odisha and Andhra Pradesh. Policy answers include better reservoir management, micro-irrigation, crop diversification away from water-intensive crops in deficit regions, and timely contingency crop plans.
Retreating monsoon
How and why the southwest monsoon leaves India.
In one line: The retreating monsoon is the withdrawal of the southwest monsoon from India, starting in the northwest in September and ending by mid-October.
Why it retreats
The monsoon depends on a low-pressure area over northwest India created by summer heating. After the September equinox, as the Sun moves south, this low weakens and high pressure builds. Winds weaken and then reverse, and the rain belt shifts south and east.
How IMD declares it
IMD declares withdrawal only after 1 September, when rain stops over an area for several days, an anticyclone forms in the lower atmosphere, and moisture falls sharply. It then draws a line of withdrawal. The 2020 revision set 17 September as the normal date to begin from northwest India and 15 October for complete withdrawal.
What the season feels like
The period of retreat often brings clear skies with high heat and humidity in the plains, sometimes called 'October heat'.
Where to go next
Long Period Average
The benchmark that decides whether a season is normal.
In one line: The Long Period Average (LPA) is the average rainfall over a long base period, used as the benchmark to judge whether a monsoon season is normal, deficient or in excess.
The numbers
IMD's current LPA for the June to September season for the country as a whole is about 87 cm, based on the period 1971 to 2020. A country-wide season is 'normal' at 96% to 104% of the LPA, 'below normal' at 90% to 95%, 'deficient' below 90%, 'above normal' at 105% to 110% and 'excess' above 110%.
Area-level categories
For a district or subdivision, IMD uses departures from its own normal: -19% to +19% is normal, -20% to -59% deficient, -60% to -99% large deficient, and +20% or more excess.
Why it is in the news
By 19 September 2026, all-India rainfall was 15% below normal and nearly 43% of the country's area was deficient.
Where to go next
Low-pressure systems in the Bay of Bengal
How a low grows into a depression or cyclone.
In one line: A low-pressure system is an area where air pressure is lower than around it; over warm seas like the Bay of Bengal it can intensify into a depression, deep depression or cyclone.
The ladder of intensity
IMD grades systems by sustained wind speed. A low-pressure area is the weakest. As winds strengthen, it becomes a depression (about 31 to 49 km/h), a deep depression (about 50 to 61 km/h) and then a cyclonic storm (62 km/h or more), with higher grades above that.
Why the Bay produces so many
The Bay of Bengal is warm, receives moisture and is often seeded by remnants of systems from the Pacific, so lows form frequently during and after the monsoon, especially in September to November.
Why it is in the news
On 19 September 2026 IMD forecast a low over the north Andaman Sea to become a depression on 21 September and a deep depression on 22 September, nearing the south Odisha-north Andhra Pradesh coasts around 23 September.
Where to go next
Northeast monsoon
The October to December rains of south India.
In one line: The northeast monsoon is the rainy season from October to December when winds blowing from the northeast bring rain to Tamil Nadu, Puducherry, coastal Andhra Pradesh and parts of Kerala and Karnataka.
How it works
After the southwest monsoon retreats, winds over the Bay of Bengal turn to blow from the northeast. They pick up moisture over the sea and shed it on the east coast of the southern peninsula. Depressions and cyclones from the Bay add much of the rain.
Why it matters
Tamil Nadu lies in the rain shadow of the Western Ghats during the southwest monsoon, so the northeast monsoon is its main rainy season. It fills its reservoirs and tanks and supports the samba rice crop.
Why it is in the news
With the southwest monsoon withdrawing and many regions in deficit, the northeast monsoon will decide water availability in the south for the coming months.
Where to go next
Take the 20 September 2026 quiz: 30 Prelims-style questions with answers