Why did it feel particularly hot the day before it turned cold, which was obviously much higher than the previous days?

First of all, cold weather is the scene of the arrival of a cold front, because the arrival of a cold front is generally accompanied by a scene of cooling and dehumidifying. Before the arrival of the cold front, the local area was controlled by the warm air mass, and the updraft prevailed. However, the arrival of the cold front forced the heating mass to rise, and the heating mass began to compress in the process of being forced to rise, so that the original heating mass would be strengthened and the temperature would be higher than the original temperature. When the cold front comes, the temperature will gradually drop. Therefore, the temperature people feel when the cold front comes will be very different from that before the cold front comes. The south and the north will be the same, but they will also be affected by the climate. In different climates, the temperature difference also increases.