What is the effect on dew point when a cold front passes?

When a cold front passes, a sharp drop in dew point occurs due to the sudden arrival of colder, drier air. As the cold front advances, it forces the warmer, moist air ahead of it to rise, which can lead to the condensation of moisture, resulting in clouds and precipitation. When the cold air replaces the warm, moist air, the dew point – which is a measure of the moisture content in the air – tends to decrease significantly. This happens because colder air holds less moisture than warmer air, leading to a notable decrease in humidity and, subsequently, a lower dew point reading.

In contrast, options suggesting a steady increase or no effect do not align with the physical principles of meteorology that govern the behavior of air masses during a cold front passage. A variable change implies unpredictability, which also does not reflect the typical and consistent changes we observe in dew point when a cold front moves through an area.