This study aims to analyse the trends and evaluate the heterogeneity of maximum temperature and precipitation during the spring and summer seasons from 1994 to 2023 at four synoptic stations in Tehran. This analysis aims to identify the patterns of warm-season climate changes and the structural stability of the time series of these variables. The nonparametric Mann-Kendall test was used to detect trends, and the Sen’s slope estimator was applied to quantify the magnitude of changes. To examine homogeneity and identify structural breaks, the Pettitt, Standard Normal, Buishand, and Von Neumann tests were employed to evaluate the temporal behaviour of temperature and precipitation with statistical rigour.

The maximum spring temperature at all four stations exhibited an increasing trend, though with varying intensity. Geophysic and Shemiran stations showed the strongest warming, and a structural break was confirmed, indicating a shift to a higher temperature phase since the early 2000s. In contrast, Mehrabad and Chitgar experienced milder increases, with no evidence of structural breaks. During summer, the increasing trend in maximum temperature was also evident, but its stability varied across stations: Geophysic recorded a clear jump in 2009, Mehrabad exhibited a low-amplitude oscillatory trend, Chitgar stabilised after an initial period of instability, and Shemiran remained stable without structural changes.

In contrast, precipitation during spring and summer showed no significant long-term trend at any station, and homogeneity tests confirmed the absence of structural breaks. These results indicate that over the past three decades, Tehran has been mainly affected by structural increases in maximum temperature, particularly in central and high-altitude stations, while precipitation lacks a long-term stable pattern. These findings highlight the importance of temperature management, energy consumption optimisation, and urban planning adapted to seasonal warming.