The weather phenomenon below the second day of science is mainly caused by the cold front crossing.

The front formed by the active movement of cold air mass to warm air mass is called cold front. Cold front is the most common front in China, and it can move all over the country. However, due to the different configurations and moving speeds of the cold front and the upper trough, the distribution of clouds and precipitation near the cold front is also obviously different, and some mainly appear behind the front; Others mainly appear in the front.

Before the cold front crosses the border: the temperature is high, the weather is clear and the air pressure is low.

When crossing the border: strong wind, cooling and rainy.

After the cold front:

1 temperature: drop

The air pressure drops first and then rises.

Precipitation: There is rain behind the front.

It's sunny.