Recent change in northward migration of the East Asian summer front and increased compound wet–hot conditions

Abstract

The East Asian summer front (EASF) plays a key role in regional precipitation and heat stress, yet its long-term positional changes remain poorly understood. Using a front-tracking algorithm applied to ERA5 reanalysis (1979–2025), we identify northward migration of the EASF during both the active frontal season and late summer, with a more robust 1.92° shift in late summer. These shifts are associated with enhanced moisture transport, regional weakening of the upper-level jet, and localized sea surface temperature warming that has intensified and spatially broadened in recent decades. This poleward displacement is associated with increased frontal precipitation over Korea and enhanced heat stress across East Asia, with a greater likelihood of their co-occurrence, particularly during late summer. Our findings highlight frontal displacement as a pathway linking large-scale atmospheric and oceanic changes to regional climate risk and offer insight to inform climate projections and adaptation strategies over East Asia.