Which factor does NOT affect lifeguard visibility?

The visibility of lifeguards plays a crucial role in ensuring the safety of swimmers. Among the factors listed, the temperature of the water does not influence lifeguard visibility. While temperature can affect the comfort and performance of swimmers and rescue attempts, it does not change how well a lifeguard can see into or across the water.

In contrast, water clarity has a direct impact on visibility; murky or cloudy water can obscure what lies beneath the surface, making it difficult for a lifeguard to spot swimmers in distress. Glare and reflection can also significantly impair visibility by creating bright spots on the water's surface, making it challenging to see swimmers. Additionally, poor lighting, especially in areas with insufficient illumination, can further hinder a lifeguard's ability to observe the water and the people in it. Collectively, these factors create conditions that can endanger both lifeguards and swimmers; however, the temperature of the water does not contribute to this visibility issue.