Marek Kučera 
OVERVIEW
Winter 2025/26 across Asia is expected to be heavily influenced by the evolving ENSO cycle, shifting towards neutral or early La Niña conditions by late winter. This transition will impact the East Asian Monsoon, the Siberian High strength, and winter storm tracks across the continent.
Other key teleconnections shaping the winter include the Arctic Oscillation (AO), the North Atlantic Oscillation (NAO), the Madden-Julian Oscillation (MJO), Quasi-Biennial Oscillation (QBO), Indian Ocean Dipole (IOD), Pacific Decadal Oscillation (PDO), and the Pacific-North American (PNA) pattern. The polar vortex’s strength and any Sudden Stratospheric Warming (SSW) events will be critical for cold air outbreaks across northern and eastern Asia.
The winter will likely begin mild in many regions due to persistent warm anomalies in the western Pacific Ocean and the East China Sea, while later months may see a pattern reversal with more frequent cold air intrusions and snow events, especially across Siberia, northeast China, and the Korean Peninsula.
REGIONAL OUTLOOKS
1. EAST ASIA & NORTHEAST ASIA
(China, Japan, Korean Peninsula, Mongolia, eastern Russia)
Temperature: Early winter favors near to slightly above normal temperatures, particularly in southern China, Japan, and the Korean Peninsula due to warm SSTs and a weak subtropical ridge. However, from January onwards, the Siberian High will strengthen, increasing the likelihood of cold air outbreaks and prolonged cold spells in northern China, Mongolia, and eastern Russia.
Precipitation: Precipitation will be near-normal to above-normal along coastal Japan and the Korean Peninsula, with increased snowfall in mountainous regions of northern Japan and northeast China. Southern China is expected to remain drier than average through December and January, with a potential increase in rainfall in February.
Snow & Extremes: Snowfall likely above average in northern Japan and eastern Russia, with increased risk of blizzards and heavy snow in Mongolia and northeast China during February. Cold spells could bring record lows in Siberia and northern Mongolia, especially if a mid-winter SSW disrupts the polar vortex.
2. CENTRAL ASIA & WESTERN SIBERIA
(Kazakhstan, Uzbekistan, Turkmenistan, western Russia)
Temperature: Generally colder than average due to the anticipated strengthening Siberian High, especially from late December through February. Cold air outbreaks into Central Asia are probable, with below-normal temperatures dominating throughout the core winter months.
Precipitation: Overall drier than average, except for localized snowfall in mountainous regions such as the Tien Shan and Altai ranges. Western Siberia may see near-normal snowfall, contributing to early spring snowmelt and runoff.
Snow & Extremes: Frequent frost and freezing conditions expected. Extreme cold snaps may lead to record low temperatures in Kazakhstan and western Siberia during January and February.
3. SOUTH ASIA & THE INDIAN SUBCONTINENT
(India, Pakistan, Bangladesh, Nepal, Sri Lanka)
Temperature: Winter temperatures are expected to be near-normal to slightly warmer than average, especially across northern India and Pakistan due to subdued western disturbances and a weak mid-winter trough.
Precipitation: Below-normal winter precipitation expected, particularly across northwest India and Pakistan, raising concerns for dry conditions and drought in some areas. The northeastern states of India and Bangladesh may experience near-normal rainfall influenced by monsoon remnants and early pre-monsoon activity.
Snow & Extremes: Snowfall in the Himalayas likely near to below average, impacting water resources for the spring melt season. Fog and cold air pooling will be common in northern India, particularly in the Indo-Gangetic Plain during December and January.
4. SOUTHEAST ASIA
(Thailand, Vietnam, Cambodia, Laos, Myanmar, Malaysia, Indonesia)
Temperature: Generally near-normal temperatures, with mild warmth in December due to lingering tropical warmth. By January and February, a slight cooling trend may occur, especially over northern parts of the region.
Precipitation: The dry season is expected to dominate with below-average rainfall across northern parts of the region. However, La Nina-driven rainfall is expected in southern countries.
Snow & Extremes: Snowfall is not typical for this tropical region, though occasional cold snaps in mountainous areas (northern Thailand and Vietnam) may lead to cooler-than-average nights.
5. NORTHERN & ARCTIC ASIA
(Siberia, Arctic Russia, Far East)
Temperature: Very cold temperatures expected, with significant below-normal temperature anomalies persisting throughout the season. Siberian High likely to be strong, driving persistent cold outbreaks and extreme frost.
Precipitation: Snow cover expected to be extensive and above average in northern Siberia, with snow depth accumulating earlier than average due to early cold onset.
Snow & Extremes: Prolonged extreme cold spells with record low temperatures possible. Strong wind chills and blizzard conditions may impact infrastructure and travel.
6. MIDDLE EAST & WESTERN ASIA
(Iran, Iraq, Turkey, Caucasus, Arabian Peninsula)
Temperature: Mixed signal region with warmer-than-average conditions expected in much of the Arabian Peninsula and southern Middle East, while northern Turkey and Caucasus could see colder conditions due to Siberian High influences.
Precipitation: Drier than average across the Arabian Peninsula and Iran. Northern Middle East and Turkey could experience near to above-normal winter precipitation, with potential snow in high elevations.
Snow & Extremes: Snowfall in mountainous regions such as the Zagros and Taurus ranges is expected near normal or slightly above normal, supporting winter tourism and water resources.
CLIMATE DRIVERS & TELECONNECTIONS SUMMARY
- ENSO: Neutral or weak La Niña by late winter, shifting monsoon patterns and mid-latitude storm tracks.
- Siberian High: Expected to strengthen in late December and persist into February, driving cold air outbreaks and extreme temperatures.
- Arctic Oscillation (AO): Positive early winter, shifting to neutral or negative in mid-winter, influencing cold air outbreaks in mid-latitudes.
- Indian Ocean Dipole (IOD): Neutral to slightly positive, potentially moderating rainfall in South and Southeast Asia.
- Madden-Julian Oscillation (MJO): Active phases in winter may enhance storm activity over East and Southeast Asia.
- Pacific Decadal Oscillation (PDO): Near neutral, possibly supporting a mixed western Pacific temperature pattern.
- Quasi-Biennial Oscillation (QBO): Westerly phase, helping to maintain strong polar vortex early but may weaken in mid-winter.
- Sudden Stratospheric Warming (SSW): Moderate risk, with potential to trigger cold air surges in late winter.
- Polar Vortex: Strong early winter, weakening possible in January-February with impacts on cold outbreaks.
- Sea Surface Temperatures (SSTs): Warm anomalies near the western Pacific and East China Sea; cooler central Pacific.
PROGRESSION MONTH-BY-MONTH (Summary)
- December: Mild to warm start for much of East and Southeast Asia, cold developing in Siberia and Central Asia.
- January: Strong Siberian High; cold outbreaks increase in northern and central Asia; mild, dry South Asia.
- February: Increased risk of SSW-driven cold air outbreaks; heavy snow in Northeast Asia and Siberia; late winter precipitation picks up in northern Japan and eastern Russia.
FINAL NOTES
Winter 2025/26 across Asia is expected to be marked by strong regional contrasts driven primarily by a weakening El Niño transitioning toward neutral or weak La Niña conditions, a strengthening Siberian High, and dynamic stratospheric influences such as the Arctic Oscillation and potential Sudden Stratospheric Warming events. Northern and Arctic Asia, including Siberia and the Russian Far East, will experience prolonged and intense cold spells with heavy snow cover, while East Asia may see a mild start shifting to colder and snowier conditions by late winter. Central Asia is forecast to be colder and drier than average, with frost and freezing conditions dominating. South Asia and Southeast Asia are likely to face near-normal to slightly warmer temperatures with below-average precipitation, raising concerns about drought and reduced winter rainfall, especially in northern India and Pakistan. The Middle East and Western Asia will display mixed patterns, with warmer and drier conditions in the Arabian Peninsula contrasting with colder, snowier conditions in the mountainous northern regions. Overall, this winter will feature a complex interplay of oceanic and atmospheric patterns that produce a patchwork of mild and harsh weather regimes across Asia, with important implications for water resources, agriculture, and energy demand.
Marek Sadowski 
