Here's a problem to solve: Which of the following data would be most useful for describing the climate of a specific area?

Among the 4 following options, which is the correct answer?

- A: average weekly wind speeds for 1 month
 
- B: daily relative humidity levels for 18 months
 
- C: total annual precipitation amounts for 2 years
 
- D: average high and low monthly temperatures for 20 years
 