For saturation to be present, what two conditions must be equal?

Saturation occurs in the atmosphere when the air is holding the maximum amount of moisture it can at a given temperature. This condition is achieved when the temperature and dew point are equal. The dew point is the temperature at which air becomes saturated with moisture and begins to condense. When these two values coincide, it indicates that the air is fully saturated, leading to the formation of clouds, fog, or precipitation.

In contrast, other choices do not represent the conditions necessary for saturation. For instance, while humidity relates to the amount of moisture in the air, it is dependent on temperature, and thus simply having humidity equal to temperature does not signify saturation. Similarly, wind speed and wind chill are related to the effects of wind on temperature perception but are not direct measures of moisture saturation in the air. Therefore, the correct correlation for representing saturation is between temperature and dew point.