(Top) Southwest monsoon season rainfall averaged over Kerala from 1901 to 2025; (Bottom) During the Northeast Monsoon rainfall, the average rainfall in Kerala was between 1901 and 2025. | Photo credit: SPECIAL ARRANGEMENT
Kerala has reason to worry about increasingly erratic monsoon behavior as its average seasonal rainfall during both the southwest and northeast monsoons has shown a steady decline over the past 125 years (1901-2025), according to a report by the Institute for Climate Change Studies (ICCS).
ICCS scientists reported that Kerala’s average rainfall during the southwest (June–September) and northeast (October–December) monsoons, the state’s primary sources of rainfall, decreased by 12.5% and 6.1% of the long-term average (LPA, 1971–2020) per year, respectively.
While the LPA for the southwest monsoon rainfall in Kerala is 1,919.3 mm, the LPA for the northeast is 478.1 mm.
Information released as part of the “Climate Statement for Kerala State: 2025” states that the average southwest monsoon rainfall during 1901–2025 showed a decreasing trend in all districts except Idukki.
Nine districts of Kottayam, Alappuzha, Kollam, Pathanamthitta, Kannur, Wayanad, Kozhikode, Malappuram and Palakkad reported a “significantly declining” trend, while Ernakulam, Thrissur and Kasaragod showed a “declining” pattern. A “non-significant increasing” trend was observed in Idukki.
In the case of the Northeast Monsoon, a decline in seasonal rainfall was recorded in all districts except Kasaragod, with “significantly decreasing” trends observed in Wayanad, Palakkad and Kottayam. Kasaragod showed an “insignificant increasing” trend.
“Although climate change is global in nature, its consequences are highly region-specific. The trends we observe in Kerala highlight how global climate change can play out differently in different regions. Given the state’s unique geography, monsoon dependence and socio-economic structure, even modest long-term changes in rainfall patterns can have significant consequences,” said Sinan Nizar, Young Scientist, ICCS.
Although the state received 2,925.7 mm of annual rainfall in 2025, a deviation of +1.2% from the LPA, officials said the average rainfall during the southwest and northeast monsoons was 87% and 79% of the LPA, respectively.
During the southwest monsoon, three districts, Wayanad (-36%), Idukki (-35%) and Malappuram (-27%), reported significantly below average rainfall. In contrast, the northeast monsoon was well below normal across the state, with eight of the 14 districts recording deficient rainfall. The most pronounced deficits were observed in Kollam (-32%) and Malappuram (-33%), followed by Idukki (-26%), Kozhikode (-24%) and Palakkad (-24%).
Despite the long-term decline in average rainfall during both monsoon seasons, Kerala remains prone to extreme rainfall fluctuations. 2023 turned out to be one of the driest in recent history due to a severe deficit in the southwest monsoon, unlike 2018 which witnessed excessive rainfall and devastating floods.
Published – 15 Feb 2026 20:42 IST