Why is the weather in Hebei yellow?

There are more water vapor and dust in the air, and the scattering characteristics of these larger coarse particles are very different from those of molecules. The longer the wavelength, the more yellow-orange light scatters, and the total scattering amount also increases significantly, so the sky is yellow.

On the contrary, the yellow sky indicates that there are big water drops and dust in the atmosphere, which indicates that there may be precipitation. Therefore, people often say "it's yellow and rainy".