Does this passage describe the weather or the climate?
The air in Boulder, Colorado, is often dry in the winter.

 - weather
 - climate
Read the text carefully.
The air in Boulder, Colorado, is often dry in the winter.
Humidity is the amount of water in the air.
This passage tells you about the usual winter humidity in Boulder. It does not describe what the weather is like on a particular day. So, this passage describes the climate.