Compound heat‐drought days (CHDDs) are frequent in eastern China's summer, peaking in June–July over North China (NC) and July–August in the middle and lower reaches of the Yangtze River (YR), threatening crops, human health and energy supplies. This study compares their thermodynamic mechanisms driving CHDDs in the two regions. Both experience lower‐tropospheric anticyclonic anomalies with enhanced subsidence, with land–atmos...