The weather is clear and the visibility is high. Why does it feel dark inside?

The better the weather, the brighter the outside and the darker the room will be. The darkness of the shadow itself is related to light. The light is weak and the shadow is weak. The stronger the light, the more obvious the contrast between the shadow and the direct place. I feel that the brighter the outside, the darker the inside, which is also the result of visual brain analysis.

Visibility:

Visibility refers to the maximum distance that a person with normal vision can identify a target from the background. That is, with the sky near the horizon as the background during the day, you can clearly see the outline of the gray target on the ground, and you can identify what it is with a viewing angle of more than 20 degrees, and you can clearly see the luminous point of the target lamp at night. In meters. Visibility is mainly determined by two factors: the brightness difference between the target and the background that sets it off. The greater (smaller) the difference, the greater (smaller) the visible distance.