In the same area, which air pressure is higher in winter or summer? why

The air pressure in winter is higher than that in summer.

Because the atmosphere is in the open space around the earth, there is no specific boundary, which is very different from the gas in a closed container. In summer, the temperature of the mainland is higher than that of the ocean, and the humidity of the atmosphere is higher (compared with winter), which makes the air of the mainland spread to the ocean continuously, resulting in the decrease of its air pressure. In winter, the temperature in the mainland is lower than that in the ocean, and the air humidity in the mainland is also lower than that in summer, so that the air in the ocean spreads to the mainland. This is why the atmospheric pressure in mainland China is higher in winter than in summer (atmospheric temperature is also a factor that affects atmospheric pressure, but the factor that determines the change of atmospheric pressure here is not temperature, but the flow and density of the atmosphere).