Which type of airspace does an airport's rotating beacon primarily serve as a weather indicator for?

The rotating beacon at an airport primarily serves as an essential weather indicator for Class D airspace, which is typically associated with smaller airports that have an air traffic control tower. These beacons are used to provide visual guidance to pilots during periods of poor visibility, such as when there’s low cloud cover or nighttime operations.

Class D airspace has a defined vertical and lateral boundary and is managed by air traffic control, making it crucial for pilots to be aware of local weather conditions when entering or departing from areas served by these beacons. Thus, the beacon helps in alerting pilots to the airport's location and its associated weather conditions, significantly enhancing safety during approach and landing.

This context emphasizes the specific role of the rotating beacon in enhancing situational awareness for pilots operating within the confines of Class D airspace.