Why does it rain in Tomb-Sweeping Day every year?

It rains in Tomb-Sweeping Day, not exactly. Every year around Tomb-Sweeping Day, it is often rainy and rainy, so Du Muyou, an ancient poet in the Tang Dynasty, said, "It rains a lot during the Qingming Festival, and pedestrians on the road want to die." Why does it always rain a lot in Tomb-Sweeping Day?

First, when winter goes and spring comes, the cold air gradually weakens, and the warm and humid air on the ocean begins to move northward actively. Before and after Qingming, cold and warm air often meet, thus forming rainy weather.

Secondly, there are many depressions in spring. The clouds in the low pressure go fast, the wind is strong and the rain is urgent. Whenever the low pressure passes, there will be rainy weather.

Thirdly, before and after Tomb-Sweeping Day, there was a lot of water vapor in the atmosphere, which easily condensed into Mao Mao rain at night. For these reasons, there were many rainy days in Tomb-Sweeping Day. Every year around April 5th in Tomb-Sweeping Day, the summer monsoon from the ocean begins to prevail in China, which will bring a lot of rain and bring convenience to farmers' spring ploughing. Therefore, there is a saying that "spring rain is as expensive as oil". Warm and humid air from the ocean will wander north and south of the Yangtze River, so there is also a saying that "spring rain is continuous". However, this does not mean that it will rain in Tomb-Sweeping Day every year. In some areas, it is often reported that Tomb-Sweeping Day caused a mountain fire during ancestor worship.