Thermal comfort is necessary for productivity in offices. However, the current standards for the thermal comfort temperature range are inaccurate for monsoon-influenced humid subtropical climatic zones due to seasonal extremes. This research paper aims to determine a thermal comfort range for naturally ventilated public offices in the monsoon season of the monsoon-influenced humid subtropical climate of Hamirpur, Himachal Pradesh. Three representative public offices were selected and studied in August 2023. The study comprised a comprehensive assessment of physical environmental factors and gathering subjective responses through questionnaires. The analysis of the objective survey revealed the occupants’ dissatisfaction with the thermal environment. The thermal comfort range for monsoon season was found to be 26.1–28.8 °C while the recorded indoor temperature was in the range of 26.6–30.1 °C. The neutral temperature was also calculated to be 27.5 °C. The study investigated the impact of the thermal parameters of the environment on thermal sensation in office buildings. It proposed a temperature range for maintaining optimal thermal conditions for offices in the monsoon season of the monsoon-influenced humid subtropical climatic zone.