How can you calculate the cloud base from temperature and dew point?

Calculating the cloud base from temperature and dew point involves understanding the difference between these two values, known as the spread. The spread represents the difference in temperature and dew point and is crucial for determining when clouds will form, as clouds typically begin to form when the temperature cools to the dew point.

The correct formula reflects that relationship. It takes the surface temperature and subtracts the dew point, yielding the spread. Dividing this spread by 4.4 provides a rough estimate of the altitude above the surface where clouds may begin to form, which is then multiplied by 1,000 to convert it into feet, a common unit of measurement in aviation.

In this context, the other options do not accurately represent the relationship needed to find the cloud base. They either miscalculate the relationship altogether or use incorrect arithmetic, thus failing to produce a valid or usable formula for determining cloud base altitude. Utilizing the temperature minus the dew point properly gives the most direct and relevant calculation for predicting cloud formation altitude.