Why the sunshine hours vary greatly. Like Chongqing? How to judge the factors affecting sunshine hours

There are many factors that affect the sunshine time, such as the position, altitude, latitude and weather of the sun. For the benefit of Chongqing, there are more sunshine hours in summer than in other seasons, because the sun is over the northern hemisphere at this time, and there are not as many sunshine hours in Chongqing as in Tibet. Although the latitude is similar, Tibet is not as high as Chongqing because of its high altitude and long sunshine hours.