Indian Ocean Dipole fuels extreme weather across Asia

Asia is facing one of its most volatile seasons in decades, as the convergence of La Nina and a strong negative Indian Ocean Dipole (IOD), the most intense since 1996, drives destructive floods, typhoons, and erratic monsoons across Southeast and South Asia.  

Sri Lanka: Cyclone Ditwah’s deadly impact  

• Cyclone Ditwah, named by Yemen after Socotra’s Detwah Lagoon, intensified from a depression near Sri Lanka’s eastern coast and moved north-northwest across the Bay of Bengal.  

• Torrential rains triggered floods and landslides, killing at least 31 people in tea-growing districts like Badulla and Nuwara Eliya, with 14 missing.  

• Over 4,000 families have been affected, with major roads closed due to landslides.  

• Advanced Level exams were postponed nationwide as schools and transport were disrupted.  

• Rivers including the Mahaweli, Kelani, and Nilwala are under flood watch, with winds reaching 60–80 km/h and seas dangerously rough.  

• The storm is forecast to move toward Tamil Nadu and Puducherry, bringing heavy rains to India through November 30.  

Thailand: Hat Yai submerged  

Southern Thailand declared disaster zones after Hat Yai recorded its heaviest rainfall in 300 years. More than 600 mm fell in days, submerging streets up to 2.5 meters deep. At least 33 people have died, with hundreds of thousands displaced.  

Vietnam: Relentless typhoons  

Vietnam’s active typhoon season has left 90 dead and 12 missing, with 200,000 homes flooded. Central cities like Hue saw record-breaking rainfall, overwhelming river basins.  

Philippines: Successive super storms  

The Philippines endured over 20 typhoons in 2025, including Kalmaegi (Tino) and Fung-wong (Uwan). Combined, they affected 6.9 million people, killed 286, and caused USD 46 million in damages.  

Malaysia: Monsoon floods  

Floods across seven states displaced 11,000 people, with over 3,000 hotspots identified during the northeast monsoon.  

India: Uneven monsoon  

Southern states faced flash floods, while Rajasthan and Gujarat reported drought warnings. Agriculture and water management remain strained.  

Pakistan: Late Rains and Water Stress  

Flooding hit Karachi and Sindh, while Balochistan continues to suffer water scarcity, raising food insecurity concerns.  

Maldives: Unseasonal storms  

The southwest monsoon in the Maldives, which typically brings steady rainfall from mid-May to November, has been unusually erratic this year. November recorded only 8–15 rainy days, yet when storms did occur they produced sudden, heavy downpours, pushing average precipitation to around 230 mm but in short, intense bursts rather than evenly spread showers. Temperatures held steady at 27–28 degrees celsius, so the anomaly was driven by rainfall patterns rather than heat. The uneven distribution left some atolls grappling with flooding while others remained unusually dry, complicating both water management and agriculture.

Experts note the negative IOD (sea surface temperatures at -1.57 degrees celsius) is pushing warm waters eastward, fueling rains in Southeast Asia while reducing rainfall in parts of South Asia. Combined with La Nina (67 percent probability for Nov–Jan), these forces are strengthening monsoon winds and driving extreme weather across the Indian Ocean basin.  

From Hat Yai’s submerged streets to Sri Lanka’s cyclone-triggered floods, Asia’s climate extremes are interconnected.

Cyclone Ditwah underscores how the Indian Ocean Dipole and La Nina have turned this season into a stark reminder: climate volatility is the new normal, demanding stronger adaptation across the region.