Why is it cold to wear tights in winter?

There is no gap between career and legs.

There is an air layer between loose trousers and the body. From the point of view of heat conduction, the thermal conductivity of air is very small, which makes the heat conduction speed very slow. Moreover, the thermal conductivity of the multi-layer flat plate composed of air layer and trousers is smaller than that of the single-layer trousers, and the smaller thermal conductivity means the same heat generated, which can keep the temperature for a longer time.

Pants themselves have no temperature, just to prevent body heat from leaking out and make people feel warm. Too tight pants will strangle subcutaneous blood vessels, hinder blood flow, block the body heat source, and make the body surface temperature drop, which is the feeling of cold.

Extended data:

Why does the human body temperature stay at around 37℃? That's because blood will provide energy to the whole body during the whole body circulation, so that the human body will be warm. If the blood circulation of the human body is blocked and some parts of the body cannot provide energy in time, it will naturally feel cold.

Clothes that fit the body will make people feel that the material is close to the skin, and cold air is not easy to enter, which makes people mistakenly think that it has a good warm-keeping effect. But in fact, this kind of close-fitting clothes, after a long time, will easily lead to the deterioration of blood circulation, leading to chills.