January 2026 marked the fifth warmest on record, despite a cold snap in Europe and North America, due to a wavy Arctic jet stream.
While the northern hemisphere faced frigid conditions, the southern hemisphere experienced extreme heat, leading to wildfires.
Sea surface temperatures remained high and sea ice extent was notably low, highlighting ongoing climate change impacts.
January 2026 was the fifth warmest January month on record, with contrasting temperatures in the northern and southern hemispheres, according to the European Centre for Medium-Range Weather Forecasts, Copernicus Climate Change Service (C3S).
Most of Europe and large parts of North America experienced a cold snap through most of January due to a wavy and unstable Arctic jet stream. Many countries in the Southern Hemisphere, such as Australia, Chile and Argentina, suffered from heightened maximum temperatures, heatwaves and wildfires.
The C3S recorded January to be 1.47°C above the pre-industrial average (1850-1900). This was 0.28°C below the highest January anomaly record of 1.75°C set in January 2025. The January weather in the Northern Hemisphere was dominated by the wavier than normal Arctic jet stream, a consequence of the rapid warming of the Arctic region.
The destabilised jet stream allowed frigid cold air into the lower latitudes, bringing heavy snowfall to many regions in Europe, North America and Siberia. As a result, Europe’s average land temperature for the month was -2.34°C, the coldest January month for the continent since 2010. “Widespread cold conditions occurred across Fennoscandia, the Baltic States, eastern Europe, Siberia and the central and eastern United States,” according to the C3S.
While Arctic was sending cold air down south, the region was itself experiencing higher than average temperatures, especially in the “Canadian Arctic Archipelago, Baffin Bay, Greenland, and the Russian Far East”.
In the Southern Hemisphere, where it is summer season right now, temperatures in southern South America, Northern Africa, central Asia, most of Australia and Antarctica were much higher than the normal. This lead to extensive and intense heatwaves in many regions and even triggered wildfires.
The excessive heat that generated wildfires in southeastern Australia in the second week of January were made five times more likely and 1.6°C hotter due to global warming and consequent climate change, according to an analysis by the World Weather Attribution (WWA) consortium.
The cold snaps on land did not have much of an impact on sea surface temperatures (SST) in the Northern Hemisphere, especially close to Europe and North America. The average sea surface temperatures between the latitudes 60°S–60°N was 20.68°C, which was the fourth highest average SST on record.
In fact “a large region of the subtropical and the northeast North Atlantic, including the Norwegian Sea, had the warmest SSTs on record for the time of year”, as per C3S. The SSTs were higher than the average in large parts of the North Pacific Ocean as well and were near normal in central and eastern Pacific Ocean, because of the prevailing weak La Nina conditions.
The warmer than normal Arctic region also led to the sea ice extent for January 2026, being six per cent below the normal, which is the third-lowest extent for this time of the year. “Regionally, sea ice concentrations were much below average in the northern Barents Sea, between Svalbard and Franz Josef Land, as well as in Baffin Bay and the Labrador Sea, coinciding with much-above-average surface air temperatures in those regions,” according to C3S.
Along with the cold air and snowfall, parts of Europe also suffered from excessive rainfall and flooding in January. The month was wetter than normal for western, southern and eastern Europe. Many regions, such as the Iberian Peninsula, Italy, western Balkans, Ireland and the United Kingdom, suffered from extreme rainfall triggered flooding.
Other regions which were wetter than the average during January were western Canada, northern Mexico, southern United States, central Asia, easternmost Russia, Japan, southeastern Brazil, northern Australia and southern Africa.
The heavy rainfall in southern Africa led to extensive floods in parts of Mozambique, Eswatini, northeastern South Africa and Zimbabwe killing 200 people and impacting thousands. The event analysed by the WWA for imprints of global warming and consequent climate change brought to light the need for Africa made weather and climate models.