The observing location may be coincident with the weather observing location; or it may be the touchdown area of the primary runway. The selected location must provide what?

• A. Consistent visually determined values
• B. The maximum data rates
• C. Proximity to the runway centerline
• D. The selected location must provide consistent visually determined values

Answer: (D)

Reliable weather observations depend on the observing location yielding consistent visually determined values. The area used for observation must produce stable, repeatable visual impressions of weather elements (like visibility, cloud cover, and precipitation) so data are comparable over time and between observers. If the location introduces varying visuals or biases, the observations become inconsistent and less useful for forecasting and safety decisions. Data rates or proximity to the runway centerline don’t guarantee this consistency, whereas ensuring consistent visually determined values does.