Record 15.4°C temperature in Antarctica on eve of austral winter

The Antarctic Peninsula experienced a record-breaking temperature of 15.4°C (59.7°F) on June 6, an unprecedented reading for the region at the onset of the austral winter. This significant heatwave, which also caused atypical ice melt, was recorded at Argentina's Esperanza Base, located on the Trinidad Peninsula.

The previous record for June at Esperanza Base was 13.3°C in 1998. The newly recorded temperature is drastically higher than the average June maximum of -6.2°C for the base. Climatologist José Luis Stella of Argentina's National Meteorological Service described the temperatures as "very high, very unusual for the time of year," noting that while much of Argentina experienced an anomalously warm start to June, the Antarctic Peninsula saw temperatures up to 20°C above normal.

Other Argentine bases also reported record highs. Marambio Base reached 11.8°C (previously 9.2°C) and San Martín Base recorded 9.4°C (previously 7.8°C). The average June maximums for these bases are typically around -10.7°C and -5.6°C, respectively. Raúl Cordero, an academic at the University of Groningen in the Netherlands, stated that this "heatwave that affected the extreme north of the Antarctic Peninsula" is not an isolated incident but confirms a trend.

Cordero warned that unless global warming is halted, such events will become increasingly frequent. Thomas Caton Harrison, a climate scientist with the British Antarctic Survey, acknowledged that climate change influences these events but noted the complexity of its effects in the region. He emphasized the need for extensive long-term data collection to understand the underlying climate patterns, given Antarctica's natural temperature fluctuations. Both specialists agree that rising temperatures are evident, with consequences like rain falling instead of snow, impacting polar ecosystems such as penguin colonies and creating challenges for researchers due to runoff and ice formation. Cordero observed that Esperanza Base has seen consecutive weeks above freezing, leaving large areas of the northern Antarctic Peninsula snow-free – an unusual sight for the winter landscape.