Why does Guiyang have so many cloudy and rainy days?

Guiyang experiences a high frequency of cloudy and rainy days primarily due to the region's high relative humidity and specific meteorological patterns. Most of the precipitation in the area is generated by atmospheric frontal activity, supplemented by convection and condensation processes.1

The province's climate is also influenced by its geography. During the summer, the southern and eastern parts of Guizhou are exposed to moist maritime air masses, which contribute to a distinct summer maximum in rainfall. These conditions result in Guiyang having more than 260 rainy and cloudy days in an average year, contributing to the city's characteristically limited sunshine.1