The sunshine time in Haixi city exceeds 3000 hours a year. Haixi Mongolian and Tibetan Autonomous Prefecture and Qinghai Autonomous Prefecture, referred to as Haixi Prefecture for short, are located in the northern part of Qinghai-Tibet Plateau and the western part of Qinghai Province. The terrain is high in the northwest and low in the southeast, which is a typical cold and dry continental climate zone.

Haixi has a long history. In ancient times, it used to be the land of western Qiang. In the Han dynasty, the eastern part under its jurisdiction was the activities of Qiang tribes such as Xianling Beihe, and the western part belonged to Ruoqiang. In the fourth year of Emperor Ping of Han Dynasty, Wang Mang set up Xihai County, and the east belonged to it. The last county of Wang Mang was abolished and restored to Qiang territory.

Definition of sunshine time

Sunshine hours refer to the time when the sun actually shines in a place. In a given time, sunshine hours are defined as the sum of all periods in which the direct solar irradiance reaches or exceeds 120 watts per square meter, with one decimal place as the unit. Sunshine hours can also be called actual sunshine hours.

Illuminable Hours Astronomical illuminable hours refer to the time required for the sun center to reach the ground from the eastern horizon to the western horizon without any shelter. Illuminable hours can be calculated by formula, and can also be found from astronomical almanac or weather table.

Sunshine percentage is equal to (sunshine hours divided by sunshine hours) multiplied by 100%, which is an integer. Sunshine hours are mainly used to characterize the local climate and describe the past weather conditions.