The objective of this study is to develop a simple and rapid method for estimating urban heat island (UHI) intensity. Using gridded data from the Central Weather Administration’s surface meteorological stations, we excluded the influence of elevation on temperature and identified the top 5% highest and bottom 5% lowest temperature values within urban areas for analysis. We examined the long-term variations in UHI intensity across four regions: the Greater Taipei area, Taichung, Tainan, and Kaohsiung. Our findings reveal distinct trends in UHI intensity among the regions. In the Greater Taipei area and Taichung, UHI intensity has shown an increasing trend over the past 63 years, while Tainan and Kaohsiung did not exhibit significant enhancement. These differences may be related to population growth and patterns of urban development. The operation of the Taichung Power Plant and the establishment of the Tainan Science Park have contributed to local temperature increases, leading to shifts in high-temperature areas. This study provides long-term data on UHI variations in Taiwan’s four major municipalities and offers scientific support for developing future strategies to adapt to urban climate change.