The Urban Heat Island (UHI) effect, whereby cities demonstrate warmer temperatures than their surroundings, elevates the risk of heat-related illnesses and mortality rates for vulnerable groups within the urban population. As urbanisation trends continue and heatwaves occur more frequently and intensely due to climate change, the UHI phenomenon is vital to research for mitigation purposes. The aim of this thesis was therefore to investigate the presence of the UHI phenomenon in Gävle, Sweden, by analysing Land Surface Temperature (LST) variations, determine high-risk zones for vulnerable populations, and assess municipal mitigation strategies. The quantitative analysis utilised remote sensing data and Geographic Information Systems (GIS), and was complemented by a qualitative interview for deeper insight into the municipality’s awareness and preparedness for UHI-related risks.  

The results confirmed the presence of a UHI around Gävle city, which was most prominent during the summer (~4°C LST difference, July 2024). Summer hotspot areas around city districts Näringen, Sörby-Urfjäll, Valbo, and Andersberg were identified and the relation between land cover and LST variations were investigated. High proportions of paved surfaces and buildings were found to be closely linked to higher LSTs, whilst more extensive canopy cover was a good indicator of cooler areas. The elderly care facilities Furugården, Vinddraget, and Attendo Murengatan as well as the preschools Orions förskola, Södergården, and Markhedens förskola, were suggested as some of the most at-risk facilities for high LSTs affecting vulnerable populations. 

Although Gävle Municipality has yet to develop a systematic approach to deal with heat-related issues, adaptation measures for other climate risks such as stormwater management can fulfil multi-functional use, especially urban tree-planting initiatives that bind water and provide cooling through shade. The municipality also plans to focus more explicitly on heat-related risks impacting vulnerable groups during the autumn of 2025, and recognises the need for more fine-scale heatmapping to support targeted interventions. So, while a systematic approach still needs to be implemented, the municipality’s planned initiatives are a promising indicator of their future UHI mitigation strategies.