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Atmospheric visibility does not always match measured air quality. During repeated observations, the atmosphere sometimes appeared clear even when particulate matter levels were moderate, and at other times appeared hazy under similar measured conditions. This study examines how atmospheric visibility varies during the transition from March to April in Seoul, South Korea. Observations were conducted at a fixed site in the Han River basin, where urban structures and open water coexist. To ensure consistency, only ground-based observations that were matched with satellite data from the NASA GLOBE Observer Clouds program (HIMAWARI-9) were included. Meteorological variables and air quality data (PM₂.₅ and PM₁₀) were used as supporting information. The results show that visibility does not respond in a simple or consistent way to individual variables. Although higher PM₂.₅ concentrations are sometimes associated with reduced visibility, the relationship is not consistent. Relative humidity also does not show a clear pattern. Instead, visibility reflects the combined influence of multiple atmospheric conditions. Differences between March and April were observed, with March showing greater variability and April showing relatively clearer conditions in some cases. However, overlapping observed patterns between the two months indicate that visibility cannot be explained by seasonal differences alone. Visual observations support these findings. Under hazy conditions, the atmosphere appears more diffuse, while clearer conditions show sharper boundaries. The plume from a combined heat and power plant provides a useful visual reference for interpreting airflow and atmospheric conditions. These observations show that visibility is not a direct indicator of air quality, but a dynamic result of interacting atmospheric conditions.