Assessing Extreme Urban Heat Events in Singapore: Local Characteristics, Temporal Trends and Heat Stress Implications

Understanding climate extremes is vital for resilience studies due to their significant short-term and long-term impacts on economic, human, ecological, and urban-physical systems. Research with climate analogues suggests that cities in tropical regions are likely to face unprecedented temperatures, necessitating preparedness for heat scenarios not yet experienced elsewhere. In this study, the changing characteristics of extreme heat events are examined for the city of Singapore. First, a range of definitions and heat-related indices are investigated for their applicability in a tropical context. Then, historical meteorological data is analyzed using a selected method based on relative thresholds. An assessment of temporal trends in key heat wave properties - namely frequency, duration, intensity, cumulative magnitude, timing, and seasonal variation - is conducted at a city-wide scale using data collected from national weather stations. Furthermore, heat stress during high-temperature periods is assessed using a network of weather stations located in high-density residential areas. Preliminary results indicate that periods of hot spells and heatwaves occur throughout the year with a higher frequency observed during the inter-monsoon season, when the wind speeds are generally lower in Singapore. Additionally, high-density urban areas experience longer periods of heat spells as compared to the suburban regions. Understanding the localized trends can help inform preparedness plans aimed at minimizing exposure among at-risk groups, particularly those with limited access to cooling solutions like air conditioning. The findings of this study contribute to the formulation of region-specific adaptation strategies to enhance heat resilience in tropical urban context.