According to global climate prediction models, the ongoing El Niño event is expected to peak between September and January. Sea surface temperature (SST) anomalies across multiple models are projected to exceed +2.5°C. Notably, forecasts from the Australian Bureau of Meteorology (BoM) project anomalies of +3.0°C to +3.5°C, while the Copernicus Climate Change Service (C3S) indicates projections as high as +4.0°C to +4.1°C, suggesting this event could potentially develop into one of the strongest on record.
Consequently, distinct global climate patterns are anticipated this winter across East Asia, North America, and Europe. Shifts in the position and meandering of jet streams, altered cyclone tracks, and regional temperature anomalies are expected to impact flight route planning and winter airport ground operations.
1. Regional Climate Outlook Highlights
East Asia (China & Japan)
Climate Trends: A mild winter baseline is expected overall, but the region will be prone to passing lows and frontal systems, tilting conditions toward wetter and snowier weather.
The subtropical jet stream will exhibit a classic El Niño wave pattern—meandering southward over southern China and curving northward near Japan.
As a result, warm, moist air will readily stream into the vicinity of Japan, driven by a strengthened Philippine Sea High. Waters south of Japan and along the Pacific coast will frequently remain under the influence of this warm airflow, making prolonged periods of severe cold exceptionally rare.
From November through January, precipitation across mainland China and Japan is forecast to be above average (wetter conditions). Furthermore, a weakened winter monsoon pattern (reduced expansion of the Siberian High) will limit cold air intrusions, keeping temperatures generally elevated nationwide. However, southern coastal lows ("Nangan lows") will track more frequently along Honshu's southern coastline, increasing the frequency of rain and, when cold air lingers near the surface, snow events in the Kanto region and surrounding areas.
Australia
Climate Trends: Northern Australian monsoon activity tends to be suppressed through November, followed by a gradual, phased transition from December into January.
In December, monsoon rainfall across northern Australia (10°–25°S / 120°–145°E) is projected to be near average.
However, moving into January past the typical peak, precipitation is forecast to drop below average. This atmospheric setup ties into the Western Pacific (WP) teleconnection pattern, which further weakens the East Asian winter monsoon and reinforces the warm winter trend across East Asia.
North America (United States & Canada)
Climate Trends: From November through January, the Pacific-North American (PNA) teleconnection pattern—a hallmark of strong El Niño events—will become exceptionally well-defined.
In the 500 hPa geopotential height field, a classic wave train pattern will dominate: negative height anomalies (deepened, eastward-shifted low pressure) over the Gulf of Alaska, strong positive anomalies (warmth) across Canada (especially the northern regions), and negative anomalies (cold air) over the central and eastern United States.
Consequently, while Alaska and Canada are likely to experience significantly warmer-than-average conditions, the central and eastern U.S. will see contrasting cold air outbreaks, creating pronounced regional disparities.
Europe and Far East Mid-to-High Latitudes
Climate Trends: From November into December, Arctic cold air outbreaks are expected to remain limited, favoring above-normal temperatures across the mid-latitudes. Much of the Eurasian continent is also likely to be dominated by positive geopotential height anomalies, associated with persistent high-pressure conditions and a generally warm pattern.
In January, Arctic cold air outbreaks are expected to become more frequent. However, the Siberian High is likely to remain weaker than normal in its southeastward expansion. This is expected to limit the direct southward intrusion of cold air across a broad area of the mid- to high latitudes, helping to maintain the overall warm pattern.
2. Impacts on Aviation and Flight Operations
Given these atmospheric trends, flight operations should anticipate and prepare for the following operational impacts:
① Enroute and Upper-Air Wind Impacts
Transpacific Routes (Asia ⇔ North America)
Atmospheric circulation changes driven by El Niño are likely to alter the strength, latitude, and alignment of the Pacific jet stream compared to seasonal averages. On transpacific routes between Asia and North America, shifts in headwind and tailwind components will impact flight times, contingency fuel planning, and optimal routing, making continuous monitoring of daily upper-air wind forecasts essential.
Intra-East Asia Routes
Meandering and intensity variations of the subtropical jet stream can cause significant changes in wind direction and speed along routes traversing these latitudes. Heightened awareness for turbulence—including Clear Air Turbulence (CAT)—will be critical in and around jet stream boundaries and core regions.
② Airport and Ground Operations (Arrival & Departure Environment)
Major Airports in Japan (Pacific Coast / Kanto Region)
While the overarching seasonal trend points to warmer temperatures, the frequent passage of southern coastal lows brings precipitation risks to airports along Honshu’s Pacific coastline. When these lows interact with lingering shallow cold air, wet snow events can occur in the Kanto plains (including Tokyo Haneda and Narita), requiring heightened preparedness for aircraft de-icing/anti-icing operations, runway surface condition management, and traffic flow adjustments due to reduced visibility.
Destinations in Central/Eastern North America and Canada
Contrasting regional temperature and snowfall patterns across North America mean central and eastern U.S. airports face elevated risks of cold-air outbreaks, snowstorms, and icing conditions. Airport operations will need to account for runway snow clearance, de-icing holdover times, and potential winter schedule disruptions.
European Destinations
Although Europe is expected to trend warmer overall, active frontal boundaries and passing low-pressure systems will still pose typical winter operating hazards, including gusty crosswinds, low ceilings, reduced visibility, and winter precipitation that require standard winter operations management.
