Which of the following marks the passage of a cold front?

A cold front is characterized by a number of distinct meteorological changes that occur as the front passes through an area. One of the most noticeable effects is a wind shift. This shift happens as the cold air mass moves in and replaces the warmer air mass, leading to changes in wind direction, often from a southerly or southeasterly direction to a northwesterly or northerly direction behind the front. This is a fundamental indicator that a cold front has passed, as the different properties of the air masses create distinct weather patterns.

Other factors, such as an increase in temperature or gradual clearing, may occur after the cold front has passed but are not definitive markers of its arrival. Similarly, while a rise in pressure may follow the passage of a cold front due to the denser, colder air exerting more atmospheric pressure, it is not as immediate or obvious a signal as a wind shift. Thus, noticing the shift in wind direction is crucial for identifying the passage of a cold front.