Why is the air pressure higher on sunny days than on cloudy days?

Caused by the proportion of water vapor.

According to the query of Yulu Learning Mutual Aid Network, the air humidity on cloudy days is generally high, and there are many components of water vapor in the air. There are fewer components of water vapor in the air on sunny days. Because the density of water vapor is lower than that of air, the air pressure on sunny days is higher than that on cloudy days. So it is caused by the proportion of water vapor.

Simply put, air pressure is the density of air, just like the air on the plateau is thin, so the air pressure is low. In the same place, if the temperature is high, the gas will expand, the density will decrease, the air pressure will decrease, the temperature will decrease, the air will contract, the density will increase and the air pressure will increase.