Why does it rain in Tomb-Sweeping Day?

It rains in Tomb-Sweeping Day, the old man said, which means this year is a good year.

Every year before and after Tomb-Sweeping Day, it is often rainy, so Du Mu, a poet in the Tang Dynasty, said in a poem: "It rains a lot during the Qingming Festival, and pedestrians on the road want to die." Why does it always rain 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.

The second is that the air pressure is much lower in spring. The clouds in the low pressure move 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 are many rains during the Qingming Festival.

Tomb-Sweeping Day is around April 5 every year, and the summer monsoon from the ocean begins to prevail in China every April, which will bring a lot of rain and bring convenience to farmers' spring ploughing production, so 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 also often reported that Tomb-Sweeping Day caused a mountain fire when he visited his ancestors. It can be seen that it is not "rainy in Qingming Festival" every year.