In order to investigate the influence of extreme winter weather and sea conditions on the design wave estimation of northern ports,using Huanghua Port as a case study,we build a comprehensive numerical wave model that accounts for the combined effects of sea ice and cold strong winds.The simulated maximum and average significant wave heights at the entrance of the outer channel of Huanghua Port are 0.41% higher and 5.46% lower than the measured,respectively,and the evolution trend is basically consistent.The results show that the maximum significant wave height,considering sea ice,strong winds,and the effects of wave diffraction and reflection,at the location of the disaster caused by the cold wave in 2018 in the harbor,is 1.14 m.Sensitivity analysis reveals that neglecting the influence of cold waves and strong winds during wave estimation within the port leads to a significant underestimation of the maximum significant wave height by 73.68%.In addition,if the effect of sea ice is considered,the significant wave height will be 8.77% lower compared to ice-free conditions.