Monsoon 2026 September Forecast India: Strong Deficit Signal as Withdrawal Begins
Key takeaways:
- September 2026 rainfall likely at 89% of LPA, marking a strongly below-normal month
- 70% probability of below-normal rainfall, highest deficit risk of the season
- East & Northeast and parts of South Peninsula to see relatively stable rainfall
- Central, Northwest & Western India likely to face widespread rainfall shortfall
The Southwest Monsoon 2026 is expected to weaken sharply during September, with rainfall projected at 89% of the Long Period Average (LPA).
In simple terms, the final phase of the monsoon is likely to be decisively below normal across most parts of India, as the season transitions into withdrawal, with only limited regions maintaining stable rainfall.
What Do the Probabilities Say? (September Outlook Explained Simply)
The rainfall outlook for September shows a dominant below-normal signal:
- 70% probability of Below Normal rainfall
- 20% probability of Normal rainfall
- 10% probability of Above Normal rainfall
This indicates a very high likelihood of deficit conditions, making September the weakest phase of the monsoon season.
As the withdrawal phase sets in, rainfall activity is expected to reduce sharply in both intensity and spatial coverage, with fewer active systems sustaining widespread precipitation.
Where Will It Rain More or Less? (State-wise & Regional Outlook)
The spatial distribution for September indicates an overall rainfall departure of around -11%, confirming a strongly deficient closing phase of the monsoon.
- Normal rainfall zones (limited support): Parts of East and Northeast India, including Bihar, West Bengal, and northeastern states, are likely to receive near-normal rainfall, supported by residual monsoon activity.
- Southern peninsula stability: Tamil Nadu and Kerala are expected to witness largely normal rainfall, aided by transitional weather systems during the withdrawal phase.
- Deficit regions (widespread concern): Central, Northwest, and Western India, including Rajasthan, Gujarat, Madhya Pradesh, Maharashtra, and adjoining regions, are likely to experience below-normal rainfall, reflecting weakening monsoon currents.
- Western coastal belt: Regions such as Konkan and South Gujarat may also see reduced rainfall activity, indicating a decline in monsoon intensity even along typically active zones.
Overall, the pattern reflects a clear withdrawal-driven monsoon structure, with rainfall becoming limited, patchy, and regionally confined.
What Does This Mean for India?
The September outlook suggests reduced rainfall support during a critical late-season phase, which may impact crop maturation, soil moisture retention, and reservoir replenishment, particularly across central and western India.
While eastern and southern regions may continue to receive adequate rainfall, the overall decline in monsoon activity will slow down water resource gains.
Major Weather Events: September 2025
A late-peaking and highly active monsoon month, September 2025 saw early withdrawal in the Northwest alongside extreme rainfall, cloudbursts, and deep depression-driven events across other regions.
Final Takeaway
September 2026 is expected to be a strongly deficient closing phase, marked by widespread rainfall shortfall, limited regional support, and a clear transition toward monsoon withdrawal across India.
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