Heat waves in South Korea have become markedly longer, highlighting a need to better understand the physical mechanisms governing their persistence. Therefore, we first categorised 52 years (1973–2024) of summer heat waves into moderately long events (MLEs; 5–9 days) and extremely long events (ELEs; ≥ 10 days) based on their duration and statistical distribution. Then, we analysed each type of summer heat wave using a stage‐ba...