Antarctica Heat Record Shattered: 20°C Above Winter Normal

Antarctica is in the grip of an extraordinary winter heatwave, with temperatures soaring more than 20°C above seasonal norms and shattering the continent’s winter temperature record. On June 6, 2026, the Argentine Esperanza Base on the Trinity Peninsula recorded a staggering 15.4°C (59.7°F) — the highest winter temperature ever measured on the continent, according to The Guardian. The reading surpassed the previous June record of 13.3°C set in 1998 by more than 2°C and came during a prolonged heatwave that has kept daily maximum temperatures above freezing for three consecutive weeks.

Context: A Continent in Deep Winter

Antarctica is currently in the depths of austral winter, when temperatures at Esperanza Base typically average -6.2°C. The fact that the mercury climbed to 15.4°C represents what climate scientists describe as a “huge anomaly.” Raúl Cordero, an Ecuadorian climate professor at the University of Groningen, told The Guardian: “This is absolutely crazy. It is also about 20°C above normal for this time of the year. That is a huge anomaly.”

The extreme warmth was not confined to a single station. Other Argentine research facilities recorded similarly unprecedented readings between June 5 and 6. Marambio Base reached 11.8°C — far above its June average of -10.7°C — while San Martin Base recorded 9.4°C. A Chilean station, Boonen Rivera, registered temperatures close to 13°C, as Euronews reported.

Landscape Transformed

The most visible impact of the heatwave has been the dramatic transformation of the Antarctic landscape. On King George Island, approximately 160 kilometers from Esperanza Base, researchers observed that the usual 20-centimeter blanket of snow had completely disappeared. Luis Muñoz, a Chilean glaciologist working on the island, described the scene to The Guardian: “Last weekend was very strange. The temperatures here went very high so everything outside melted. Usually there is 20 cm of snow and a lot of ice on the ground at this time.”

Muñoz and a colleague climbed to the 500-meter summit of the nearby Collins glacier and were astonished to find rain falling on the ice. “There was a direct impact on the glacier, which should be receiving snow now. It should not be suffering ablation at this time of the year. This is obviously not good for the glacier,” he said. The landscape, he noted, had changed “from predominantly white to brown, grey and green.”

Sea Ice in Crisis

The heatwave is unfolding against a backdrop of severe sea ice loss across the Antarctic region. The Bellingshausen Sea — which should be covered in sea ice during June — is nearly ice-free for the fourth time in three years. Will Hobbs, an Antarctic sea ice expert at the University of Tasmania and the Australian Antarctic Program Partnership, expressed frustration to Chinese state media: “It’s frustrating. It’s now June and there is no sea ice there.”

According to data cited by CGTN, total Antarctic sea ice currently stands at 11.4 million square kilometers, compared to the long-term average of 12.6 million square kilometers — a loss of 1.2 million square kilometers. Compared to the 1991-2020 average, sea ice west of the Antarctic continent has lost approximately 650,000 square kilometers, an area roughly the size of France.

Ecological and Global Implications

The consequences of this warming extend far beyond the Antarctic Peninsula. Phil Reid of the Australian Bureau of Meteorology warned that if protective sea ice remains absent for extended periods, floating ice shelves in front of Antarctic continental glaciers could break up faster, accelerating glacier melt and future sea level rise.

Scientists have warned that major glaciers such as Thwaites and Pine Island may be approaching or may have already passed tipping points that could ultimately raise global sea levels by four meters. The Antarctic ice sheet as a whole holds enough water to raise global sea levels by approximately 58 meters.

Ecologically, the impacts are already being felt. Emperor penguin colonies in the Bellingshausen Sea experienced catastrophic breeding failure in late 2022, with thousands of chicks dying. This led the International Union for Conservation of Nature to upgrade the emperor penguin from “Near Threatened” to “Endangered” earlier this year. Krill populations — the foundation of the Antarctic food chain — also rely on sea ice for habitat and face an uncertain future.

What Caused the Heatwave?

Scientists attribute the event to a combination of factors. Cordero explained that the heatwave was driven by “extremely strong westerlies” carrying warm air from the north across the Antarctic Peninsula — a phenomenon that has been occurring with increasing frequency since the 1980s and is linked to climate change. The absence of sea ice compounds the problem, as open water allows warm air masses to reach the continent without the cooling buffer that ice normally provides.

This event follows a pattern of extreme Antarctic temperature anomalies. In July-August 2024, parts of East Antarctica experienced temperatures up to 28°C above average. Research published in npj Climate and Atmospheric Science found that human-caused climate change made that heatwave both stronger and more likely, and that such events could become up to 20 times more frequent by the end of the century under high emissions scenarios.

What’s Next

The situation is further complicated by the anticipated development of a potentially strong El Niño event. The World Meteorological Organization reported on June 2, 2026, an 80% probability of El Niño formation between June and August, with near-certain persistence through November. Most models predict at least moderate strength, with potential for a strong event that could amplify global temperature anomalies.

José Luis Stella of the Argentine National Meteorological Service described the temperature anomaly as “an unusual phenomenon,” while researchers at the University of Groningen and elsewhere continue to study the complex feedback loops between sea ice loss, atmospheric warming, and glacier dynamics in one of Earth’s most sensitive regions. As scientists have emphasized, the future of Antarctica depends on the choices made today regarding greenhouse gas emissions.