Why is there foggy weather?

Fog weather mainly refers to a weather phenomenon in which the horizontal visibility is less than 500 meters due to numerous small water droplets or small ice crystals suspended in the air near the ground.

Generally speaking, there are three main conditions for the formation of fog: first, there is a lot of water vapor in the near-surface layer, that is, the humidity in the air is very high. Secondly, if the water vapor in the air near the ground is supersaturated, small water droplets will be formed. The third is that there are a lot of dust and smoke particles in the air. When fog forms, it is often accompanied by the corresponding inversion layer, that is to say, the closer to the ground, the lower the temperature and the higher the temperature. This is just the opposite of normal weather.

Fog usually forms gradually at night and reaches its highest concentration in the morning. After the sun comes out, with the increase of ground temperature, the dense fog will gradually become thinner until it dissipates. Therefore, there is a saying that "ten fogs and nine sunny days". If it does not dissipate for a long time, it may rain.

Safety warning in foggy days: generally in foggy days, try to reduce going out as much as possible. You'd better wear a mask when you have to go out. Try to exercise as little as possible in foggy days, and don't exercise in foggy days. Pedestrians should see the passing vehicles clearly when crossing the road. Vehicles and cars should drive slowly, obey the instructions of the traffic police, don't catch the car (boat), and don't crowd the ferry when it stops.