The morning glow indicates how the weather will change.

The morning glow indicates that the weather will turn cloudy and rainy. Sunglow is the result of sunlight passing through the atmosphere around sunrise and sunset and being scattered by a large number of air molecules. The more impurities such as dust and water vapor in the air, the stronger the color. The morning glow before and after sunrise indicates that a lot of water vapor has appeared in the atmosphere, and clouds have begun to invade this area, indicating that the weather will turn cloudy and rainy.

When sunlight enters the atmosphere, it will scatter when it meets atmospheric molecules and particles suspended in the atmosphere. These atmospheric molecules and particles themselves do not emit light, but because they scatter sunlight, each atmospheric molecule forms a scattered light source.

According to Rayleigh scattering law, light with shorter wavelength such as violet, blue and cyan in the solar spectrum is most easily scattered, while light with longer wavelength such as red, orange and yellow has stronger light transmission ability. So we see that the clear sky is always blue, while the light above the horizon is only yellow, orange and red with longer wavelengths. After these rays are scattered by impurities such as air molecules and water vapor, the sky there will be colorful.

Before and after sunrise in the morning, sometimes bright red brilliance can be seen reflected in the eastern sky or clouds, making the blue sky more magnificent. But before long, dark clouds soon filled the whole sky, and then it began to rain. On cloudy days, such as in the evening or around sunset, we see this bright red glow in the western sky or clouds, but it indicates that the weather will clear up the next day. This is the origin of "Don't go out at dawn and go to Wan Li Road at sunset".