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

Because the temperature is high on sunny days, the air is dry and the air density is high, so the air pressure is high; On the contrary, the low air pressure is due to the low temperature on cloudy days, high water content in the air and low air density. In addition, the air pressure in winter is higher than that in summer, because the temperature in winter is lower than that in summer, the air contracts, the density is high and the pressure is high, so the air pressure in winter is higher than that in summer.

Air pressure knowledge:

Air pressure is the atmospheric pressure acting on the unit area, that is, it is numerically equal to the gravity of the vertical air column extending upward to the upper limit of the atmosphere. The famous experiment in the Madeborg hemisphere proved its existence. The international system unit of air pressure is Pascal, abbreviated as Pa, and the symbol is PA.

In meteorology, people usually use kilopascals (kPa) or hectopascals (hpa) as units. Other commonly used units are bar (bar, 1 bar = 100000 Pa) and centimeter mercury column (or centimeter mercury column). Air pressure varies not only with height, but also with temperature. The change of air pressure is closely related to the change of weather.