Why is there more fog in spring and summer but less in autumn and winter?
This is because low ground temperature is a condition for fog, but not a condition for rain.
Fog is the condensation of water vapor in the air near the ground. There are two basic conditions for the formation of fog. One is that there is sufficient water vapor content in the air near the ground, and the other is that there is a low-temperature layer near the ground. The water vapor in the low-temperature air reaches saturation due to the low temperature, and then condenses into fog.
The conditions for rain to form are often high ground temperature and low altitude temperature. The hot and humid air masses on the ground rise because their density is lower than the cold air masses, and the temperature continues to drop during the rise. The saturated water content of the air decreases as the temperature decreases. When the temperature of the hot and humid air mass rising from the ground drops to the saturated air humidity, the gaseous water begins to condense into water droplets. If the temperature is low enough, the water vapor can directly condense into ice.
As long as the supply of water vapor is sufficient and the temperature is low enough, small water droplets will continue to condense and merge into large water droplets. When the gravity of a large water droplet exceeds the buoyancy of the air, the water droplet will fall downward. As long as they do not encounter dry hot air masses and are evaporated, the raindrops will continue to fall to the ground and become rain. So when it fogs up, it won't rain anymore. Extended information
In autumn and winter, after the cold air from the north moves southward, as the weather clears and the sun shines, the moisture content in the air gradually increases, which easily forms radiation fog. Therefore, the fog in autumn and winter can often Good weather is forecast for tomorrow.
The fog in spring and summer is different. Most of it comes from the warm and moist air flow from the sea. When it hits the colder ground, the lower air also becomes colder, and the water vapor condenses into fog. This kind of fog is called advection fog. It is formed when warm and moist air from the sea invades the continent and suddenly encounters cold. When these warm and moist air currents meet the dry and cold air from the continent, it will naturally become cloudy and rainy. Therefore, fog in spring and summer indicates cloudy and rainy weather.
Baidu Encyclopedia-Fog