Weihai lies in the transition zone between a Humid subtropical and humid continental climate (Köppen Cwa/Dwa), but as it is at the eastern end of the Shandong Peninsula, its climate is strongly influenced by the surrounding Yellow Sea.
Summers are hot and humid, and August averages 24.7 °C (76.5 °F); the annual mean is 12.48 °C (54.5 °F). More than two-thirds of the annual precipitation occurs from June to September, and there are nearly 2,540 hours of sunshine per year.
Springtime warming and autumn cooling are delayed by one month, winds are generally high, and the average diurnal temperature variation throughout the year is small—at only 6.73 °C (12.1 °F).
Winters are cold and dry, but still warmer than inland places located at the same latitude; the average temperature in January is −0.9 °C (30.4 °F).