When does the sun cast the longest shadows?

The sun casts the longest shadows when it is low in the sky. This typically occurs during the early morning and late afternoon or evening when the sun is closer to the horizon. The angle of sunlight at this time is shallow, causing objects to cast longer shadows.

In contrast, when the sun is directly overhead, such as at noon, shadows are much shorter because the light is coming straight down, reducing the shadow's length. Similarly, when the sun is high in the sky, the sun's rays are coming at a vertical angle, leading to shorter and more compact shadows. During sunset, although the sun is low, shadows do not get as long as those cast in the later afternoon hours because they are still being elongated by the angle of the setting sun.

Therefore, the periods when the sun is low in the sky are key to understanding why shadows are longest, as the increased angle of incidence dramatically increases their length.