Which of the following is a reason for taking greater care with night observations?

Taking greater care with night observations is primarily due to the limitations of human vision in darkness. At night, the ability to perceive environmental cues effectively diminishes significantly because less natural light is available. This can make it challenging to accurately assess conditions such as visibility, distances, and even the details of cloud cover or other significant weather phenomena.

Additionally, the human eye is less sensitive to color and detail in low light, which can lead to misinterpretations of visual information that may be readily available during the day. For instance, distinguishing between different types of clouds or accurately gauging their heights can become problematic at night.

While factors like lower visibility and potentially increased flight traffic are relevant, they do not encompass the core reason that demands greater caution during night observations. Higher chances of instrument failure, while a valid concern, is not directly related to the nighttime conditions or human observational capabilities. Thus, focusing on the inherent challenges posed by the limitations of human vision at night is critical for ensuring safety and accuracy in weather observations.