During which conditions is "reduced visibility" most likely to occur?

Reduced visibility is most likely to occur during conditions such as fog or heavy rain. These weather phenomena significantly hinder the ability to see long distances. In fog, moisture in the air forms tiny droplets that scatter light, creating a thickening haze that obscures objects and landmarks. Similarly, heavy rain can create a curtain of water that blurs visibility, making it difficult to discern anything beyond a short range. In contrast, sunny clear days typically provide excellent visibility, calm sea states do not inherently affect visibility, and the act of anchoring does not correlate directly with reduced visibility conditions. Thus, fog and heavy rain are the primary conditions that contribute to reduced visibility.