What does the term "dew point" refer to?

The term "dew point" specifically refers to the temperature at which air becomes saturated with moisture. When the air cools to this temperature, it can no longer hold all the moisture in the form of water vapor, leading to condensation. This is an important concept in meteorology, as it helps determine humidity levels and the potential for precipitation or fog formation. The dew point is a crucial indicator of how much moisture is present in the air; higher dew point values indicate more humidity.

In contrast, the other options address concepts related to moisture but do not accurately define the dew point. For instance, the onset of rainfall is associated with other atmospheric processes, while humidity levels are measured by different metrics, such as relative humidity. Additionally, while cloud formation relates to saturation levels, it does not specifically indicate the dew point but rather the overall atmospheric conditions like temperature and pressure.