To investigate the thermal and relative humidity characteristics during the dry season in Kunming's Chenggong New District, this study selected three observation routes and conducted parallel mobile observations on November 27th–28th, 2022, and January 10th–11th, 2023. The routes encompassed various land use types and underlying surfaces. After processing the data, the results were imported into ArcGIS 10.6 to create band-like distribution maps of temperature and relative humidity for subsequent analysis. The results demonstrate that in the study area, daytime urban heat island intensity slightly surpasses nighttime intensity during the dry season, with an average daytime urban heat island intensity of 2.5 °C and a nighttime urban heat island intensity of 2.1 °C. A significant urban heat island effect is observed in industrial and residential areas. The rates of change for temperature and humidity are 1.3, −0.6 °C per h, and −3.9, 2.7% per h, respectively, with daytime variations being significantly greater than nighttime ones.