What is the relationship between air pressure and whether it will rain or not?

High and low pressure readings are indicators of the weight of the atmosphere pushed down to a specific area. When the pressure is low, air can freely rise into the atmosphere, where it cools and condenses. This condensation can form a cloud composed of water droplets and ice crystals. Finally, tiny particles such as water vapor and dust in the cloud condense into rain. If there is no low pressure, most of the air and the water vapor in it will not condense high enough, and it will not rain. This is why when the low pressure comes, rain often follows.

Low pressure brings continuous rainfall.

The intensity of rain is different, so even rainy weather does not often appear. When there is long-term stable rainfall, it is generally because of the position of the low-pressure system relative to the warm front. Warm and humid air enters the low pressure area and is pulled up by the cold air quality in front of the warm front. This will lead to a longer and more lasting rain and snow cycle.

Low pressure and high temperature thunderstorm

When the low pressure is directly in front of the cold front, the warm and unstable air in front may become a thunderstorm in the low pressure area rotating counterclockwise. This situation will produce the most serious thunderstorms, and in many areas, short-term heavy rains often occur in spring and summer. The lower the air pressure, the more air can rise to form storm clouds. Generally speaking, the higher the clouds, the greater the possibility of thunderstorms.

Cause of low pressure

The sun is the main reason for the pressure difference around the world. Due to the rotation of the earth and the rising and setting of the sun, all parts of the world will be affected by various temperatures at any given time. The temperature difference will also affect the air pressure in this area. The atmosphere will constantly adjust, trying to balance the pressure on the earth. Because the period of air pressure fluctuation is driven by temperature change, the high and low pressure areas will move back and forth, resulting in different weather in different places.