A Discussion on Water Vapor (Moisture)

QUESTION 1:

In the winter, if the air temperature was 40 F and the dewpoint was also 40, what would the relative humidity be? Now, in the spring, if the air temperature was 70 and the dewpoint was 70, what would the relative humidity be? In which situation would if feel more humid? What does this tell you about relative humidity?

If the air temperature and dewpoint temperature were both 40, the relative humidity would be 100 percent. Likewise, if the air and dewpoint temperature were both 70, the relative humidity would again be 100 percent. Despite the relative humidity being the same in both cases, it certainly would feel more humid if the air and dewpoint temperatures were both 70 degrees. This shows how the relative humidity tells you little about the actual moisture content of the air (much more moisture is contained in the air for the summer case), and how the same relative humidity value can occur in completely different situations having very different "feels" to our bodies.

Back to Discussion on Water Vapor