Monsoon Onset and Withdrawal: Quick Answer
The southwest monsoon's normal onset over Kerala is 1 June. It normally covers the entire country by 8 July and starts withdrawing from west Rajasthan on 17 September (current IMD normals, as used in IMD's end-of-season report for 2026). In 2026 the monsoon reached the South Andaman Sea on 16 May (6 days early), set in over Kerala on 4 June (3 days late), covered the whole country on 9 July and began withdrawing on 19 September (2 days late), as per IMD's statement of 30 September 2026.
Exam trap: Older textbooks and IMD's older glossary give 15 July for covering the whole country and 15 September for the start of withdrawal. Those were the pre-2020 normals. IMD's 2026 report uses 8 July and 17 September. If both appear in options, pick the one the question's source implies; for current-affairs questions, use the newer dates.
For the full climate chapter, see Indian Climate Notes for SSC.
Normal Dates of the Southwest Monsoon
| Event | Normal date | Source |
|---|---|---|
| Onset over South Andaman Sea | 22 May | IMD 2026 report (states 16 May was "6 days earlier than the normal date of 22 May") |
| Onset over Kerala | 1 June | IMD 2026 report; IMD glossary; NCERT |
| Mumbai and Kolkata | Between 10 and 13 June | NCERT Class 11, Ch. 4 |
| Covers entire country | 8 July (current normal) | IMD 2026 report |
| Withdrawal begins, west Rajasthan | 17 September (current normal) | IMD 2026 report |
NCERT adds that the monsoon "sets in over the Kerala coast by 1st June and moves swiftly to reach Mumbai and Kolkata between 10th and 13th June", and that "by mid-July, southwest monsoon engulfs the entire subcontinent".
Monsoon 2026: Actual Dates (IMD, As of 30 September 2026)
| Event | 2026 date | Compared with normal |
|---|---|---|
| South Andaman Sea and Nicobar Islands | 16 May | 6 days early |
| Kerala onset | 4 June | 3 days late |
| Most of the country covered | By 30 June | — |
| Entire country covered | 9 July | 1 day late (near normal) |
| Withdrawal begins (west Rajasthan) | 19 September | 2 days late |
| Season rainfall (June–September) | 759.4 mm, 87% of LPA | Deficient |
IMD also notes the 2026 advance was 7–10 days late over Maharashtra, Gujarat, Madhya Pradesh, Chhattisgarh and Odisha and 5–10 days late over north-east India, but near normal over north-west India. IMD's own forecast for Kerala onset (26 May ± 4 days) missed by 8 days; IMD said this was only the second miss (after 2015) since its operational onset forecasts began in 2005. For the rainfall numbers, see rainfall distribution in India.
How the Monsoon Arrives: The Mechanism (NCERT)
- Heating of the land: in April–May the sun is overhead near the Tropic of Cancer; an intense low forms over north-west India.
- ITCZ shifts north: the Inter Tropical Convergence Zone moves to about 20°N–25°N over the Gangetic plain by July (the monsoon trough).
- Trade winds cross the equator: the south-east trades cross the equator between 40°E and 60°E, turn right due to the Coriolis force and become the south-west monsoon.
- Jet streams switch: the westerly jet withdraws from the north Indian plain and the easterly jet sets in along about 15°N; NCERT holds the easterly jet "responsible for the burst of the monsoon".
- Two branches: the Arabian Sea branch (west coast, central India, Saurashtra and Kachchh) and the Bay of Bengal branch (north-east India and up the Ganga plain).
The sudden heavy first rain is called the "burst" of the monsoon. A gap of one or more weeks without rain during the season is a "break" in the monsoon.
Withdrawal and the Retreating Monsoon
| Point | Fact (NCERT unless stated) |
|---|---|
| Why it retreats | The monsoon trough moves south as the sun moves south |
| First area to lose the monsoon | West Rajasthan (normal start 17 September per IMD 2026 report) |
| Retreating monsoon months | October and November |
| "October heat" | Clear skies, high temperature and humidity after the rains make the weather oppressive |
| Where it still rains | Eastern part of the peninsula; October–November are the rainiest months there |
| Cause of that rain | Cyclonic depressions from the Andaman Sea crossing the east coast; deltas of the Godavari, Krishna and Kaveri are frequent targets |
IMD calls October–December the post-monsoon season and uses the term northeast monsoon for it; in coastal Tamil Nadu this is the main rainy season, giving nearly 60% of annual rainfall (IMD glossary). Read northeast monsoon in India and cyclones in India.
Onset vs Withdrawal: Quick Comparison
| Point | Onset (advance) | Withdrawal (retreat) |
|---|---|---|
| Direction | South to north (Kerala first) | North-west to south (west Rajasthan first) |
| Speed | Sudden ("burst") | Gradual |
| Weather after | Heavy rain, temperature falls 5–8°C (NCERT) | Clear skies, "October heat" |
| Normal start | 1 June (Kerala) | 17 September (west Rajasthan) |
Monsoon Onset and Withdrawal: 10 Practice MCQs
Q1. The normal date of monsoon onset over Kerala is: (a) 15 May (b) 1 June (c) 10 June (d) 1 July Answer: (b).
Q2. In 2026, the monsoon set in over Kerala on: (a) 26 May (b) 1 June (c) 4 June (d) 9 June Answer: (c). IMD.
Q3. The monsoon withdrawal normally begins from: (a) Kerala (b) West Bengal (c) West Rajasthan (d) Assam Answer: (c).
Q4. Which jet stream is linked to the "burst" of the monsoon? (a) Subtropical westerly jet (b) Tropical easterly jet (c) Polar jet (d) Somali jet Answer: (b). As per NCERT.
Q5. The south-east trades cross the equator between which longitudes to become the south-west monsoon? (a) 10°E–30°E (b) 40°E–60°E (c) 70°E–90°E (d) 90°E–110°E Answer: (b).
Q6. In 2026, the monsoon covered the entire country on: (a) 30 June (b) 8 July (c) 9 July (d) 15 July Answer: (c).
Q7. "October heat" refers to: (a) Pre-monsoon heat waves (b) Hot, humid weather after the monsoon retreats (c) Western disturbances (d) Loo winds Answer: (b).
Q8. A gap of one or more weeks without rain during the monsoon is called a: (a) Burst (b) Break (c) Retreat (d) Onset Answer: (b).
Q9. Which part of India gets most of its rain in October–November? (a) Punjab (b) Rajasthan (c) Coromandel coast (Tamil Nadu) (d) Konkan coast Answer: (c).
Q10. The 2026 monsoon reached the South Andaman Sea on 16 May. Compared with the normal date, this was: (a) 6 days early (b) On time (c) 3 days late (d) 10 days late Answer: (a).
More practice: Indian climate MCQs for SSC, SSC CGL geography mock test 01, SSC CHSL geography mock test 01.
Monsoon Onset and Withdrawal FAQs
When does the monsoon reach Kerala?
Normally on 1 June. In 2026 it arrived on 4 June, three days late, as per IMD.
When does the monsoon cover the whole of India?
The current IMD normal is 8 July; in 2026 it covered the country on 9 July. Older sources give 15 July.
When does the monsoon start withdrawing?
Normally from west Rajasthan around 17 September (current normal). In 2026 withdrawal began on 19 September.
What is the burst of the monsoon?
The sudden onset of heavy rain with thunder and lightning at the start of the season, which brings temperatures down sharply.
Why does Tamil Nadu stay dry in June–September?
Its coast lies parallel to the Bay of Bengal branch and in the rain shadow of the Arabian Sea branch, so its main rain comes later, in October–December.
Practice Next for Indian Geography
- Related: Western disturbances in India, El Niño, La Niña and IOD, Drought and floods in India
- Crops: Kharif, rabi and zaid crops
Sources: IMD, Salient Features of the 2026 Southwest Monsoon (30.09.2026); NCERT Class 11, India: Physical Environment, Chapter 4 Climate; IMD Pune, Met Glossary. Last checked 7 November 2026.