What does a beacon's activation at an airport signal during daylight?

When a beacon is activated at an airport during daylight, it indicates that weather conditions are below Visual Flight Rules (VFR) minimums. This is particularly important for pilots, as it serves as a visual cue that the visibility or cloud cover may not meet the criteria required for safe visual navigation.

In general, VFR minimums require that pilots have a certain level of visibility and cloud clearance to operate aircraft safely without relying on instruments. Therefore, the activation of the beacon acts as an alert for pilots to be vigilant and prepare for potential instrument flying if they are approaching the airport or planning to fly in the vicinity.

By understanding this signal, pilots can take the necessary precautions, such as reviewing their approach procedures or deciding whether to delay their flight until conditions improve.