Why is the wind so strong on a sunny day?

Because wind is air thermal convection caused by solar radiation, first of all, solar radiation cannot directly heat the air, but it will penetrate the air and be absorbed by the ground. The ground will convert sunlight into heat radiation to heat air, and the volume of hot air will expand and the density will decrease. As buoyancy will rise, cold will sink to form convection. This is a vertical movement called updraft. At the same time, solar radiation will also cause horizontal motion, because the earth is round. Due to the problem of curved surface, the radiation intensity of different dimensions is different, which will produce temperature difference, and the air layer, that is, wind, will be formed through convection interaction, so it is easy to blow when there is sun in the daytime, and the wind will stop without the heating effect of solar radiation after the sun sets. Of course, there are exceptions, and that is the monsoon caused by complex atmospheric effects. Of course, its energy also comes from the sun, but the positive energy is more and more lasting.