Why is it always hot before cooling down?

This phenomenon has a professional meteorological name, called "warm front" phenomenon. There are two main reasons for this phenomenon. On the one hand, because the cold air has not yet arrived, under the control of the heating mass, the local temperature is relatively high, and the southerly wind prevails, which is conducive to the temperature rising and warming.

On the other hand, the reason is that in the process of cold air going south, the cold air quickly squeezes and compresses the warm air that originally occupied the local area to a certain range, thus making the warm air gather and warm. The faster the cold air moves south, the more obvious the squeezing effect and the more obvious the warming effect.

Extended data

The cold front is the strongest in winter, which can often directly drive South China and South China Sea, resulting in cold wave weather. The cold front in summer is weak, mainly in the north, and it often brings thunderstorms.

North China is the only place for cold front activities in China. In Northeast China, there are cold fronts all year round, especially in spring and autumn. There are three sources of cold front in these two areas: West Road, Northwest Road and Beibei East Road. The cold front in winter mainly causes cooling and strong winds, and thunderstorms can occur in summer. In spring, cold fronts often cause strong winds and precipitation in Northeast China, but only sandstorms in North China.