Evidence of Heatwaves: Characteristics and Trends in Selected Ghanaian Cities

Heatwaves and extreme weather events exert significant impacts on human life, property and socioeconomic development. These heatwaves can lead to heatstroke, kidney failure, cardiovascular diseases, droughts, stunted growth, crop failure, wildfires and increased energy consumption for cooling. Climate change further exacerbates their effects, particularly in urban areas where excessive heat accumulates. Despite the substantial risks posed by heatwaves, Ghana lacks awareness and a standardised metric for characterising these events. To address this gap, we analysed observed maximum and minimum temperatures spanning 1960–2018 to identify heatwaves and assess their characteristics and trends. Our findings revealed that heatwaves occur during both daytime and nighttime, often coinciding with major crises such as the 1983 drought, wildfires, power rationing and economic recession. Across cities, heatwaves are becoming more frequent, especially at night. Tamale experiences stronger and more persistent heatwaves than other cities, while Accra shows a faster warming trend. The study provides evidence-based insights, creating the foundation for monitoring and assessing heatwaves in Ghana. This work lays the groundwork for developing early warning systems to mitigate risks associated with extreme heat events. Furthermore, the study's findings will inform public health authorities and policymakers, enabling them to implement targeted measures safeguarding citizens from climate-related threats and advancing progress towards Sustainable Development Goals 3, 11, 13 and 15.