Guwahati/Agartala, Oct 2 — Though the process of withdrawal of the Southwest Monsoon has started from parts of western India, its retreat from the Northeastern region has not yet been confirmed, with the eight-state region recording a 26 per cent deficit in average rainfall during the four-month monsoon season from June to September, officials said on Friday.
A senior official of the India Meteorological Department (IMD) said the department is yet to confirm the withdrawal of the Southwest Monsoon from the Northeastern region, although the withdrawal process had already begun in parts of western India, including Rajasthan and parts of Madhya Pradesh.
“Last year (2025), the Southwest Monsoon withdrew from the Northeastern region on October 14,” the official told IANS.
According to IMD data, among the eight Northeastern states, Sikkim, Tripura, Mizoram and Nagaland recorded rainfall within the normal category during the four-month monsoon season from June to September. However, Mizoram and Tripura recorded 19 per cent and 16 per cent deficient rainfall, respectively, while Sikkim and Nagaland recorded 9 per cent and 6 per cent excess rainfall, respectively.
As per IMD norms, rainfall ranging from 19 per cent deficient to 19 per cent excess is categorised as normal.
Among the other four Northeastern states, Meghalaya recorded the largest deficiency of 60 per cent during June to September, followed by Manipur with 46 per cent, Arunachal Pradesh with 44 per cent and Assam with 28 per cent deficient rainfall.
Meghalaya, which generally receives substantial rainfall, recorded only 1,077.1 mm of rainfall (actual) during June to September this year against its predictable normal rainfall of 2,695.3 mm, resulting in a large deficiency of 60 per cent, according to the IMD.
An IMD statement said rainfall over the country as a whole during the 2026 Southwest Monsoon season from June to September was 87 per cent of its Long Period Average (LPA).
All-India Southwest Monsoon rainfall was 759.4 mm, the fourth lowest since 2001 and the 13th lowest since 1901.
According to the IMD, seasonal rainfall over Northwest India, Central India, South Peninsular India and Northeast India was 94.1 per cent, 97 per cent, 76 per cent and 74 per cent of their respective LPAs, respectively.
Rainfall over East and Northeast India was 1,017.1 mm, the lowest since 1901, while South Peninsular India recorded 542.0 mm, the fourth lowest since 1901 and the second lowest since 2001. However, Central India received rainfall in the normal category during the monsoon season.
According to agricultural scientists and IMD officials, adequate rainfall during the Southwest Monsoon, particularly in July, is crucial for the Kharif season, as sowing activities across most parts of the country, including the mountainous Northeastern region, gather momentum during this period.
A senior official of the Manipur Agriculture Department said the 46 per cent deficiency in monsoon rainfall, coupled with the prolonged ethnic conflict, had severely affected agriculture in the state, where irrigation facilities remain inadequate.
“However, the state government has taken adequate arrangements and other supportive measures to facilitate farming activities in both the Imphal Valley and the hill districts during the Kharif cropping season,” the official told IANS.
The Southwest Monsoon advanced into substantial parts of the Northeastern region on June 7, two days later than its normal onset date. Officials of the IMD’s Meteorological Centres in Guwahati and Agartala said the Southwest Monsoon covered the entire Northeastern region by June 10.
The IMD had earlier revised its forecast for the four-month Southwest Monsoon season from June to September, with concerns over El Niño conditions continuing to persist. However, despite the prevailing El Niño conditions, meteorologists remained hopeful that the Northeastern region would receive adequate rainfall before the withdrawal of the Southwest Monsoon from the region.
The IMD's operational criteria for declaring the withdrawal of the Southwest Monsoon include cessation of rainfall activity for five consecutive days, establishment of an anticyclone in the lower troposphere and a considerable reduction in moisture content.
(Sujit Chakraborty can be contacted at sujitchakrabortyne@gmail.com)