Cloud amount distribution law

The total cloud cover in China is quite different between north and south. The higher the latitude, the less cloud cover. At the same latitude, there are more clouds in the east than in the west, especially in the southwest, northeast and northwest of Xinjiang.

The distribution of total cloud cover in China is closely related to the characteristics of monsoon climate. The cloud cover is the highest in summer, especially in May, June and July, and the average total cloud cover can reach 60% ~ 70%, and it is generally less in winter.

Since 2000, the annual average daytime total cloud cover in China has shown an obvious upward trend. The change of cloud cover affects sunshine, and the sunshine hours in China have decreased obviously in recent ten years, which is lower than the average of 2449 hours in most years.

The weather forecast of sunny, partly cloudy, cloudy and cloudy days that we often use is divided according to the amount of clouds. There is no cloud in the sky, or the total cloud amount is less than 1% as "sunny", and the total cloud amount 1-3 becomes "partially cloudy"; 3-7 becomes "cloudy", and it is "cloudy" when the cloud amount is above 80%.