What index should I look at if I want to judge whether it is cloudy or sunny by the data of the weather station? Is it the temperature? Radiation intensity? Or something else?

If you want to judge whether it is cloudy or sunny by weather station data, it depends on the atmospheric humidity index. Atmospheric humidity is the degree of humidity in the air, indicating the degree of water vapor content in the atmosphere from atmospheric saturation at that time. Generally speaking, the degree of atmospheric humidity is expressed as a percentage of relative humidity. At a certain temperature, the smaller the relative humidity in the atmosphere, the faster the evaporation of water vapor;

On the contrary, the greater the relative humidity in the atmosphere, the slower the evaporation of water vapor. In people's real life, the dry air in winter and spring and the sultry weather in summer are all due to the change of humidity in the atmosphere.

Extended data:

Atmospheric humidity and human health

The heat lost by the human body also depends on the saturation of water in the atmosphere. Generally speaking, the air saturation deficit at 37℃ is called physiological saturation deficit, which is of great significance to the evaporation of water vapor during human breathing. Atmospheric humidity has great influence on human body's heat metabolism and water and salt metabolism. Under different humidity conditions, the heat dissipation mode of human body is different.

Therefore, atmospheric humidity and temperature often have an impact on human health. In cold and humid weather, because the water vapor in the atmosphere absorbs the thermal radiation of the human body, the human body feels cold and is easy to catch cold; In the hot and humid season, the moisture in the atmosphere will hinder the evaporation of human body surface and affect the heat dissipation process. Perspiration is not timely, and people are prone to heatstroke.

When the temperature is low in winter, humid air is prone to rheumatism and tracheitis. If the relative humidity reaches more than 80%, it will hinder people's evaporation and heat dissipation, which will adversely affect people with kidney disease, tuberculosis and chronic waist and leg diseases.

When the humidity in the atmosphere is too low, it will cause people's skin to be dry, especially those who work outdoors for a long time, especially prone to chapped hands and feet. Therefore, paying attention to atmospheric changes is conducive to protecting human health.

Therefore, it is of great significance to pay attention to the changes of weather and atmospheric humidity at all times and do a good job of labor protection for human health. Increasing indoor air humidity in winter and spring and dehumidification in summer are beneficial to human health. People feel the most comfortable meteorological conditions are the temperature between 22-25℃ and the atmospheric humidity around 50%.