Cloud formation doesn't take place until the dew point temperature is reached because there is no saturation of air at this point.
This is defined as the temperature in which the air needs to be cooled to in order to achieve a relative humidity of 100%.
When the dew point temperature is reached, the relative humidity at constant pressure is 100% which is the criteria for cloud formation.
Read more about Dew point here https://brainly.com/question/14984865