Although Cangzhou is a coastal city, why is it dry and humid?

Cangzhou is located in the eastern part of Eurasia, in the mid-latitude zone, with a warm temperate semi-arid and semi-humid monsoon climate. Annual average dryness 1.2- 1.5, continental climate 63.8-66.0. The general climate is: four distinct seasons, moderate temperature, abundant sunshine, rain and heat in the same season, concentrated precipitation, and disastrous weather often occurs, including spring drought, summer waterlogging, cool autumn and dry winter.