What skin is called when the skin changes with temperature?

Human skin changes with the climate. Guidance: Because the weather is cold. The temperature drops. Vascular contraction. The blood flow is slow. The skin appeared. A darker color. It's very hot. The temperature rises. Blood vessels dilate and blood flows faster. Light complexion.

The hotter the weather, the whiter they will look, and the colder the weather, the darker their skin will be. So what is the hotter and whiter the skin? Why is the skin white when it is hot and black when it is cold?

When the weather is hot, because the skin temperature is lower than the outside temperature, a lot of heat will accumulate inside the skin, which will lead to particularly active blood circulation. Blood will easily penetrate into the skin surface through small blood vessels on the skin surface. At this time, the metabolism level of the skin will be enhanced due to the acceleration of blood circulation, and the skin color will become whiter than usual. When the weather is cold, the body temperature is much higher than that outside. Under the influence of the law of conservation of energy, the temperature in the body will decrease, resulting in the blood circulation of the skin being blocked, and the blood is difficult to penetrate into the skin surface, thus causing the skin to lose vitality and the surface color to turn purple-black.