The Urban Heat Island (UHI) effect is a phenomenon where the surface energy budget is altered in urban areas due to human modification to the environment, causing elevated near surface air temperatures. Understanding how different climates and large-scale climate drivers affect the behaviour of the UHI Intensity (UHII) needs further exploration. Moreover, existing literature is lacking in sufficiently describing the linkage from short-term weather patterns to long-term climate trends in cities and its role in affecting UHII. Despite the substantial volume of downscaled climate projections that exist, the suitability of these climate projections for detailed urban planning in evolving urban environments needs to be investigated. The study utilises existing climate data and climate projections to assess the patterns of UHII at various spatial and temporal scales to address these research deficiencies for Australian capital cities. Varying UHII behaviour was noted in different climate zones, which demonstrated patterns consistent with the seasonal cycles unique to each climate zone. A consistently positive UHII was observed during night-time and just before sunrise, indicating that the anthropogenic effect on the urban climate is quantifiable at night. Thus, the analysis of long-term climate trends in cities using the daily minimum temperature (Tmin) revealed that cities have been experiencing a more rapid warming trend compared to their rural surroundings. Moreover, it was found that downscaled climate projections do not adequately capture UHI effects and local climate variability in cities.