Understand the principle of weather by observing the sky.

1 Seeing a rainbow on a rainy night, why does it indicate that it will be sunny soon?

Because rainbows all appear in the opposite direction of the sun, when rainbows appear in the west, it means that there are a lot of water droplets in the western atmosphere, and it will rain locally as the weather system moves from west to east; The rainbow is in the east, indicating that there are a lot of water droplets in the atmosphere in the east. As the weather system has moved eastward, it will not rain locally in the future.

If you can clearly see the mountains and tall trees in the distance, why do they portend rain?

It seems clear that the air has high water vapor content and strong refraction. When the water vapor is supersaturated, it will rain.

Why is the sunset glow red in the evening, indicating that the weather will be fine tomorrow?

The sunset glow shows that the clouds have gone eastward, and the convection generally weakens at night, and it will clear up in the future.