Abstract: Under the background of global warming, the Yellow River Basin has experienced two consecutive low water periods over the past hundred years (1922–1932 and 1990–2002), which have seriously threatened the region’s water resources security. This study compares precipitation characteristics between these two periods and explores the weather causes from the perspectives of atmospheric circulation and sea surface temperature anomalies. The results show that the 1990–2002 period exhibited a more intense precipitation deficit than 1922–1932, corresponding to widespread drought in the middle reaches of the Yellow River Basin. Both periods displayed similar mid-latitude atmospheric circulation anomalies, including an enhanced 500 hPa Lake Baikal High accompanied by weakened low-level southwesterly winds, leading to insufficient water vapor transport into the basin. However, significant differences in circulation patterns were observed at high and low latitudes. For example, the polar vortex was weak and the subtropical high extended eastward during 1922–1932, whereas during 1990–2002, the polar vortex was enhanced and the subtropical high shifted westward. Sea surface temperature anomalies in both periods were characterized by colder conditions in the North Pacific and warmer conditions in the equatorial central-eastern Pacific. This paper also defines the Lake Baikal high-pressure index and the Pacific Ocean sea surface temperature index (calculated as the sea surface temperature of the North Pacific minus that of the equatorial central-eastern Pacific), both of which show significant correlations with the annual runoff of the Yellow River Basin and can serve as indicators for predicting hydrological abundance or decline. The findings offer technical support for water resources management and decision-making in the Yellow River Basin.