When it rains at night, the sky may appear brighter due to a phenomenon called "sky glow" or "light pollution." There are a few reasons for this:
Reflection of artificial lights: Raindrops act as mirrors, reflecting the artificial lights from street lamps, buildings, and other sources. This reflection scatters the light in different directions, illuminating the surrounding area and making the sky appear brighter.
Diffusion of light: Raindrops in the air scatter and diffuse light. When there is rain, the moisture in the air increases, causing more scattering of light. This scattering effect can make the sky appear brighter.
Cloud cover: Rain is often accompanied by cloud cover. Clouds can reflect and scatter light from various sources, including city lights. When rain combines with clouds, it can enhance the scattering and reflection of light, contributing to the brightness of the night sky.
It's worth noting that the level of brightness during rainy nights can vary depending on factors such as the intensity of rainfall, the density of cloud cover, and the amount of artificial lighting in the area.