Seasonally Responsive Residential Façades in Monsoon-Influenced Salalah, Oman: A 384-Case Pareto Screening of Solar Exposure and Daylight Access

Salalah, Oman, differs from conventional Gulf hot-arid climates because the Khareef monsoon changes cloud cover, solar availability, and outdoor conditions. This study investigates whether residential façade design priorities should vary by season and orientation. A 384-case factorial matrix combines four orientations, four window-to-wall ratios, four recess depths, and six external-shading archetypes. A reduced-order solar and diffuse-sky aperture screening model is coupled with Pareto analysis so that solar protection and sky access are treated as competing objectives. Salalah Airport TMYx (2011–2025) data were additionally analyzed to validate the seasonal radiation representation and to test the robustness of the seasonal ranking. The TMYx record gives an annual GHI of 2196.63 kWh/m2 and shows a Khareef (July–September) DHI/GHI ratio of 0.379, compared with 0.200–0.266 in the other three design periods. Sixteen representative cases were also re-evaluated in a 4 m × 5 m × 3 m reference room using a 72-point workplane; this cross-model check reproduced the original rankings for direct solar exposure (Spearman ρ = 0.983) and diffuse-sky transfer (ρ = 0.926). The annual Pareto front remains dominated by north-facing cases. For the south façade, seasonally selectable shading reduces the normalized screening-space distance by approximately 20% in the original screening; sensitivity tests using TMYx monthly radiation yield approximately 25%, while constant-diffuse and solar-path-only controls yield 25.5% and 25.2%, respectively. These percentages are screening-space effects, not energy or LM-83 daylight improvements. The study provides a reproducible early-design framework for identifying façade families that merit subsequent high-fidelity daylight and energy simulation.