Record-Breaking Winter High Temperatures in June 2026 over the Antarctic Peninsula

On 5–6 June 2026, the Antarctic Peninsula (AP) recorded high temperatures in the austral winter, with a daily maximum surface air temperature (SAT) of 15.4°C at Esperanza Station, which is 19.1°C higher than the 1991–2020 mean. In this study, using ERA5 reanalysis and observations, we investigated this high-temperature event and its mechanisms. The results show that the daily average SAT at Esperanza Station remained over 0°C for eight days starting 3 June before reaching a peak on 5 June. These high temperatures were also recorded by other AP stations, such as the Great Wall Station and San Martin Station, with daily average SATs on June 6 of 2.0°C and 6.4°C, respectively. ERA5 indicates that a blocking high-pressure system over the Drake Passage-Scotia Sea resulted in enhanced northwesterly wind anomalies over the AP, bringing more heat to Esperanza Station. In this circulation context, a strong foehn effect formed over the eastern AP, due to the central AP’s narrow and steep terrain. This vertical motion triggered the SAT increase during this event, while diabatic heating maintained the high temperatures. In contrast, horizontal advection dominated the SAT increase at Great Wall Station. These results indicate that the winters in the Antarctic are possibly facing increasingly high temperatures in the context of global warming.