FAA Ground School Practice Test

What is the temperature forecast at 9000 ft for DEN?

1. +2 degrees C

2. -2 degrees C

3. -4 degrees C

4. +4 degrees C

The correct answer is: -4 degrees C

To determine the temperature forecast at 9000 feet for Denver (DEN), it's important to consider the general lapse rate in the atmosphere, which is approximately 2 degrees Celsius per 1000 feet of ascent in the troposphere. Given that Denver is situated at an elevation of about 5,280 feet, if the surface temperature is relatively mild, a temperature drop is expected as you ascend. In this context, the forecast of -4 degrees Celsius at 9000 feet indicates a significant cooling as one rises from the warmer surface temperature to the cooler upper atmosphere. This is consistent with atmospheric principles, as temperatures indeed decrease with altitude until reaching a certain point where inversion or different atmospheric conditions may apply. The choice of -4 degrees Celsius suggests a forecast that considers typical temperature variations with altitude and the geographical climate influences in Denver, implying that conditions are cool at higher elevations.