Precession Affects the Timing and Duration of Summer and Rainy Season in East Asia

Abstract East Asia is a densely populated center whose economic and agricultural activities depend heavily on a suitable seasonality of temperature and precipitation. Geological records, like speleothems and lake sediments, show precession drives orbital‐scale temperature and precipitation variations in this region but lack seasonal detail. By reconstructing a full precession cycle using Alfred Wegener Institute Earth System Model, here, we examine how precession impacts the timing and duration of the East Asian summer and rainy season. The results reveal that in a precession cycle with high eccentricity, summer duration varies by up to 57 days, with onset and termination shifting by up to 48 and 52 days, respectively. The rainy season duration varies by up to 21 days, with onset and termination shifting by up to 31 and 35 days. These changes stem from precession‐modulated perihelion timing, affecting surface temperature and the meridional shift in subtropical high system. These findings may refine the interpretations of the complex paleoclimate proxies and offer insights into precession‐driven climate dynamics in subtropical regions, supporting future climate projections.