# Monsoon 2026: Why Odisha Got Excess Rain When India Was Deficient — Bay of Bengal Low-Pressure Systems Explained

By Shivam Singh, Founder & Mentor, Minimalist IAS · Published 26 Sept 2026 · Updated 14 Oct 2026
Source: https://www.minimalistias.com/blog/odisha-wettest-monsoon-bay-of-bengal-deep-depression

> India's 2026 southwest monsoon ended 12.6% below normal, yet Odisha was the only meteorological subdivision with excess rain, 29% above normal. How Bay of Bengal low-pressure systems explain the contrast, how IMD grades them, and how to use the season in GS1 and GS3.

**Odisha received excess rain in the 2026 southwest monsoon because a run of low-pressure systems from the Bay of Bengal kept crossing its coast, even as an El Niño year left India as a whole 12.6% short.** Odisha ended the season 29% above its normal of 1,150.2 mm, the only one of India's 36 meteorological subdivisions with excess rainfall (IMD).

> **Why in news:** IMD's season-end review shows the 2026 southwest monsoon closed at 87% of the long period average, the fourth-lowest since 2001, with Odisha the lone subdivision in the excess category. A deep depression late in the season then brought floods to north coastal Andhra Pradesh.

**Updated (October 2026):** season-end IMD figures replace the mid-season numbers; Odisha's rank, the system count, and a comparison table (monsoon depression vs cyclone) are new.

## Key facts at a glance

Start with the headline numbers; the rest of this page explains why they point in opposite directions.

*Figure: Bar chart of 2026 southwest monsoon rainfall as a percentage of the long period average: Odisha 129%, Central India 97%, All India 87% (759.4 mm against 868.6 mm), South Peninsula 76%, and East and Northeast India 74%, the lowest since 1901.*

- **All India:** 759.4 mm against a long period average (LPA) of 868.6 mm → 87% of LPA, a 12.6% deficit; fourth-lowest since 2001 and 13th-lowest since 1901 (IMD).
- **By region:** Northwest 94.1%, Central 97%, South Peninsula 76%, East & Northeast 74% of LPA; East & Northeast India (1,017.1 mm) was the lowest since 1901.
- **Subdivisions:** 18 normal (53% of area), 17 deficient (42%), 1 excess: Odisha (5%).
- **Odisha:** 1,484.3 mm, 29% above normal and the fourth-highest since 1901 (record: 1,542.1 mm in 1961); Baleshwar was the wettest district at 1,907.1 mm.

## Why was Odisha wet in a dry year?

An all-India deficit and an Odisha surplus can coexist because the two have different drivers: one is a large-scale circulation, the other a sequence of local weather systems.

- **El Niño pulled the national total down:** warm central and eastern Pacific → weaker monsoon circulation over India; IMD described El Niño as moderate and strengthening during the season.
- **The Bay kept producing systems:** ten systems affected Odisha, namely 2 deep depressions, 3 depressions, 2 well-marked low-pressure areas and 3 low-pressure areas (reports citing IMD data).
- **The track decides who gets rain:** monsoon lows form over the head of the Bay and move west-northwest along the monsoon trough, so Odisha's coast is often the first landfall.
- **Result:** about 1,058 mm of Odisha's 1,484 mm (roughly 71%) fell in about 42 days under these systems.

**Analogy:** think of the monsoon trough as a riverbed in the sky and each low as a boat floating down it. El Niño lowers the water level over the whole country, but the boats still pass the same landing, Odisha, and unload their cargo of rain there.

**Worked example:** Odisha normal 1,150.2 mm; actual 1,484.3 mm → excess = 334.1 mm → 334.1 ÷ 1,150.2 ≈ 29%.

## How is a monsoon depression different from a cyclone, and how does IMD grade them?

The systems above differ in strength; IMD grades north Indian Ocean systems by **maximum sustained wind speed**, not by central pressure alone.

*Figure: IMD classification of low-pressure systems by sustained wind speed, from low pressure area (below 31 km/h) to super cyclonic storm (above 221 km/h); a deep depression is 50–61 km/h*

| IMD class | Wind (km/h) |
| --- | --- |
| Low Pressure Area | below 31 |
| Depression | 31–49 |
| Deep Depression | 50–61 (not named) |
| Cyclonic Storm | 62–88 (first named class) |
| Severe Cyclonic Storm | 89–117 |
| Very Severe Cyclonic Storm | 118–166 |
| Extremely Severe Cyclonic Storm | 167–221 |
| Super Cyclonic Storm | above 221 |

| Feature | Monsoon depression | Tropical cyclone |
| --- | --- | --- |
| Season | June–September | Mostly pre-monsoon (April–June) and post-monsoon (October–December) |
| Usual strength | Depression or deep depression | Cyclonic storm or stronger |
| Track | West-northwest along the monsoon trough, over land | Often recurves; weakens after landfall |
| Main damage | Rain and floods | Wind, storm surge and rain |

## What was at stake: what did the late-season deep depression do?

The classification matters because rain, not wind, did the damage when a deep depression came ashore near Kalingapatnam, on the Odisha–Andhra border, in late September 2026.

- **Strength:** winds of about 55–65 km/h at landfall (media reports of IMD bulletins): a deep depression, never a named cyclone.
- **Andhra Pradesh:** heavy inflows swelled the Nagavali and Vamsadhara in Srikakulam district; hundreds of villages were flooded (media reports). Both rivers rise in southern Odisha, so Odisha's rain reaches Andhra downstream.
- **Lesson:** an unnamed system can flood more than a named cyclone; preparedness cannot wait for a name.

The wider stake is statistical: a national average hides extremes (South Peninsula 76%, Odisha 129%). That is the case for district-level forecasts and basin-wise flood warnings.

## What UPSC asks

Both questions below test the drivers behind monsoon anomalies, the theme of this page.

**UPSC CSE Prelims 2017, GS Paper I:**  
**With reference to 'Indian Ocean Dipole (IOD)' sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct?**  
**1. IOD phenomenon is characterised by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean.**  
**2. An IOD phenomenon can influence an El Nino's impact on the monsoon.**  
Select the correct answer using the code given below:  
(a) 1 only  
(b) 2 only  
(c) Both 1 and 2  
(d) Neither 1 nor 2  
**Answer: (b) 2 only.** IOD compares the western and south-eastern tropical Indian Ocean, not the Eastern Pacific. See the [IOD and El Niño sections of the monsoon guide](https://www.minimalistias.com/blog/indian-monsoon-el-nino-iod-northeast-monsoon-upsc-notes).

**UPSC CSE Mains 2014, GS Paper I:**  
**"Most of the unusual climatic happenings are explained as an outcome of the El-Nino effect. Do you agree?"** (10 marks, 150 words)  
Use 2026 as the example: El Niño explains the national deficit, not Odisha's excess.

**See the detailed explanations:** [Prelims 2017](https://www.minimalistias.com/pyqs/prelims/2017) · [Mains 2014 papers](https://www.minimalistias.com/pyqs/mains) in the free PYQ vault, with year-wise analysis. Free to browse; free sign-up to download.

## Mentor’s note

- **Quote the season as a percentage of LPA, by region and subdivision.** IMD frames it that way; the four regions are Northwest, Central, South Peninsula and East & Northeast India.
- **Do not call Odisha's season the wettest ever.** It was the fourth-highest since 1901, behind 1961, 2006 and 1956; rank claims need the full series.
- **Prelims swaps 'depression' and 'deep depression'.** Learn 31, 50, 62 and 89 km/h as boundaries.
- **In GS1 and GS3 answers, split the season in two.** El Niño and IOD set the all-India total; Bay systems set the regional split. Quote 87% of LPA, Odisha +29%, East & Northeast lowest since 1901.

## Prelims traps and 60-second revision

> **Traps: (1) IMD grades by wind speed, not by pressure alone. (2) Deep depression is 50–61 km/h and is not named; naming begins at cyclonic storm. (3) IOD is a Western vs south-eastern Indian Ocean contrast, not Indian vs Pacific. (4) Odisha's 2026 total was the fourth-highest since 1901, not a record.**

- **Q: What was the all-India monsoon in 2026?** 87% of LPA (759.4 mm), a 12.6% deficit.
- **Q: Which subdivision got excess rain?** Odisha, 29% above normal.
- **Q: Which class is 50–61 km/h?** Deep depression.
- **Q: Which two drivers explain the split?** El Niño (national deficit) and Bay of Bengal systems (Odisha).
- **Q: Where do monsoon lows form and move?** Head of the Bay; west-northwest along the monsoon trough.

## Practice: Prelims MCQs

**Q1. Consider the following statements regarding low-pressure systems over the north Indian Ocean:**

1. **A 'Deep Depression' has a higher maximum sustained wind speed than a 'Depression' but a lower one than a 'Cyclonic Storm'.**
2. **The India Meteorological Department classifies such systems solely on the basis of central atmospheric pressure.**
3. **A system is given a name only after it reaches the 'Cyclonic Storm' stage.**

How many of the above statements are correct?  
(a) Only one  
(b) Only two  
(c) All three  
(d) None

**Answer: (b) Only two**  
**Explanation:**  
**Statement 1 is correct:** a deep depression is 50–61 km/h, between a depression (31–49) and a cyclonic storm (62–88).  
**Statement 2 is incorrect:** IMD grades by maximum sustained wind speed.  
**Statement 3 is correct:** naming begins at cyclonic storm (62 km/h or more).

## Practice: Mains question

> **An all-India monsoon deficit can coexist with floods in individual States. Explain with reference to low-pressure systems over the Bay of Bengal. (Answer in 150 words; 10 Marks)**

## Terms to know

- **LPA:** long period average, the mean seasonal rainfall over a 50-year base period.
- **Monsoon trough:** the elongated low-pressure zone along which monsoon lows and depressions travel.

## Frequently asked questions (FAQs)

### How much rain did India get in the 2026 monsoon?

India received 759.4 mm against a long period average of 868.6 mm. That is 87% of normal, a 12.6% deficit and the fourth-lowest monsoon since 2001, according to IMD.

### Why did Odisha get excess rain in 2026?

A series of Bay of Bengal low-pressure systems, including two deep depressions, crossed or skirted the coast, so Odisha ended 29% above normal despite El Niño. It was the only subdivision with excess rain.

### What is a deep depression?

A deep depression is an IMD class of low-pressure system with maximum sustained winds of 50–61 km/h. It is stronger than a depression (31–49 km/h) but weaker than a named cyclonic storm (62–88 km/h).

## Related reading

- [Indian monsoon: mechanism, El Niño, IOD and the Northeast monsoon — UPSC notes](https://www.minimalistias.com/blog/indian-monsoon-el-nino-iod-northeast-monsoon-upsc-notes)
- [Revise the NCERT basics of the Indian monsoon in NCERT Foundations](https://www.minimalistias.com/resources/ncert)
- [Practise previous-year Geography questions in the free PYQ vault](https://www.minimalistias.com/pyqs)
- [All Daily UPSC Briefs](https://www.minimalistias.com/resources/daily-brief)

## Sources

- [IMD — Salient features of the 2026 southwest monsoon season](https://mausam.imd.gov.in/Forecast/marquee_data/Salient_Features_SW_MONSOON%20_2026_30_sep.pdf)
- [IMD RSMC New Delhi — tropical cyclone classification and naming](https://rsmcnewdelhi.imd.gov.in/)
- [UPSC — Civil Services (Preliminary) Examination 2017, General Studies Paper I](https://upsc.gov.in/)

From [The Daily UPSC Brief](https://www.minimalistias.com/resources/daily-brief), 5 October 2026 — by Shivam Singh.

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