Enhancing urban microclimates design is essential in hot arid climates to improve outdoor thermal comfort (OTC) and mitigate the urban heat island (UHI) effect. This study aims to evaluate the impact of modifying albedo surfaces as a heat mitigation strategy (cooling impact) to enhance OTC particularly within hot arid climates. Utilizing ENVI-met5.6.1 microclimate software and mean radiant temperature (Tmrt) as a key indicator, Al Karama-district in Dubai, UAE, serves as the case study. Proposed scenarios focused on adjusting cool reflective materials (albedo) on vertical and horizontal surfaces, and altering the height-to-width (H/W) aspect ratio, to assess their relative impact on OTC. The scenarios are categorized into three-groups in plot-A01: Group-A (horizontal surfaces with increased albedo), Group-B (horizontal surfaces with vertical cladding adjustments), and Group-C (aspect ratio modifications).Results indicate that highly reflective horizontal surfaces intensify heat stress, with Scenario-M2 (high-albedo walls and pavements) showing a significant increase in Tmrt (78–87.5 °C), a 26.5% rise from the baseline. Similarly, Scenario-M7 (high-albedo pavements with high H/W ratio) recorded the highest Tmrt values (67–88 °C) achieving a significant rise of approximately 26.8% relative to the baseline. In contrast, lower-albedo materials and higher H/W ratios yielded favorable outcomes. Scenario-M8 (high H/W ratio and low-reflectivity walls) achieved the lowest Tmrt values (52–67 °C), reflecting a 5% reduction from the baseline. These insights underscore the complex interplay between albedo, urban design strategies, and microclimates, emphasizing the importance of strategic material selection and design modifications to mitigate heat stress and enhance urban thermal conditions.