Why is the weather different between cold air and warm air? Doesn't warm air contain a lot of water vapor, which will cause precipitation?

Because cold air is heavier than hot air, under hot air, when cold air passes through the boundary, it is easy to push the hot air away, so it is very violent soon, resulting in a large air flow. So it is prone to rain, snow and strong winds.

When crossing the border, the warm wind is not easy to push away the cold wind, and the airflow is small, so the weather changes little, and it rains continuously in one place.

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