Mapping urban heat islands in Durban (2010–2025). A longitudinal ecological remote sensing study.

BackgroundUrban Heat Islands (UHIs) are an escalating environmental and public health concern in rapidly urbanising cities, particularly in the Global South. Durban, a major coastal city in South Africa, has undergone significant land-use and land-cover transformation over recent decades, potentially intensifying surface temperature dynamics. Understanding long-term UHI trends is essential for supporting climate-resilient urban planning, reducing heat-related risks, and promoting sustainable city development. MethodsThis study adopted a longitudinal ecological remote sensing design to assess UHI dynamics in Durban between 2010 and 2025. Multi-temporal Landsat and Sentinel satellite imagery were used to derive land surface temperature (LST) and classify land-cover types. Spatial analysis techniques were applied to examine temperature distribution patterns, while temporal trend analysis and correlation statistics were used to evaluate associations between LST and land-cover changes, including built-up expansion, vegetation loss, and coastal proximity. ResultsFindings indicate a consistent intensification of UHI patterns over the 15-year period. Mean LST in densely built-up areas increased from 28.4 °C in 2010 to 31.2 °C in 2025 (+2.8 °C), while vegetated zones recorded a smaller increase of +1.2 °C. Impervious surface expansion (approximately 20%) showed a strong positive correlation with elevated LST values (r = 0.76, p < 0.01). Inland urban zones demonstrated a statistically significant warming trend (β = 0.18 °C per year, p < 0.05), whereas areas with high vegetation cover and coastal influence exhibited cooling effects of up to 2 °C relative to industrial zones. RecommendationsUrban planners and policymakers should prioritise green infrastructure development, protect and restore vegetated areas, and integrate heat mitigation strategies into land-use planning frameworks. Institutionalising remote sensing-based monitoring systems is essential to support evidence-based climate adaptation and sustainable urban management in Durban.