When do rainbows usually appear?

It often appears after thunderstorms or showers in summer.

Rainbow, also known as rainbow crossing, often appears after thunderstorms or showers in summer, or when the sky here is raining, there is still strong sunlight in the sky, and many small water droplets are floating in the sky. When sunlight hits water droplets in the air, they are also reflected at different angles.

Rainbow is an optical phenomenon in meteorology. When sunlight hits the raindrops in mid-air, the light is refracted and reflected, forming an arched color spectrum in the sky. Rainbow is a natural phenomenon, which is caused by the reflection and refraction of sunlight when it hits water droplets in the air.

Because water scatters light and breaks down into seven ribbons: red, orange, yellow, green, cyan, blue and purple, the arched seven-color rainbow in the sky becomes the rainbow we see. The bigger the water drops in the air, the brighter the rainbow. We can't see the rainbow facing the sun, only the rainbow behind us, so the rainbow appears in the west in the morning and in the east at night.