What is a key characteristic of a cold front?

A cold front is characterized by a rapid decrease in temperature as it passes. This phenomenon occurs because cold air, which is denser than warm air, displaces the warm air ahead of the front. As the warm air is forced to rise, it cools quickly, leading to a notable drop in temperature over a short distance. Along with this temperature change, cold fronts are often associated with changes in weather patterns, such as increased winds, precipitation, and a shift in humidity levels.

In contrast, while other options touch upon temperature and humidity changes, they do not reflect the defining rapidity of temperature change associated with cold fronts. A slow temperature increase would describe a warm front rather than a cold front, consistent humidity levels do not adequately depict the instability cold fronts introduce, and low altitude cloud formation is present in various weather scenarios, not uniquely defining a cold front.