Why does the entire sky turn red in the evening before a rainstorm?

The entire sky turns red in the evening before a rainstorm, mainly due to the scattering of sunlight by the atmosphere.

In clear weather, air molecules in the atmosphere have a relatively strong scattering effect on sunlight, mainly scattering blue light in sunlight and rarely scattering red light. This makes the sky appear blue to us.

However, before a heavy rainstorm occurs, due to the increase in water vapor and suspended particulate matter in the atmosphere, the scattering effect of air molecules in the atmosphere on sunlight increases, especially the scattering of blue light. This results in a decrease in blue light and a relative increase in red light, making the entire sky appear red.

In addition, the onset of heavy rains is often accompanied by the development of cyclonic wind fields. This wind field will roll up a large amount of water vapor and suspended particles, further enhancing the scattering effect in the atmosphere and making the sky appear deeper. red.

In short, the entire sky turns red in the evening before a rainstorm. This is due to the increased scattering of sunlight by the atmosphere, resulting in a decrease in blue light and a relative increase in red light. This phenomenon is often seen as a precursor to heavy rain.