This paper analyzes nighttime light (NTL) intensity in Phoenix, Arizona from 1992 to 2024 using harmonized DMSP-OLS (Defense Meteorological Satellite Program Operational Linescan System) and VIIRS (Visible Infrared Imaging Radiometer Suite) datasets. By integrating a space–time cube with Emerging Hot Spot Analysis, the study identifies persistent, intensifying, and emerging patterns of urban growth. The results show sustained expansion of the urban core alongside rapid suburban development. The findings demonstrate that NTL data provide an effective proxy for urbanization and highlight the value of space–time analysis for understanding long-term urban dynamics. The methodology is transferable and can be applied to other cities worldwide for monitoring urban growth and spatial development.