This paper reports the study results from a field comfort survey of people in hot humid climate of Songkhla, a province in southern Thailand (latitude 7.20°N and longitude 100.59°E). Thermal sensation, thermal acceptability, and thermal preference were assessed from the observations of three hundred subjects in air-conditioned spaces in buildings. The analysis showed that the operative temperature for the thermal neutrality (TVS=0) was 26.3°C, and the acceptable temperature range (TVS=±0.5) was 25.6-27.1°C. The air movement played a key role to improve the people thermal sensation and preference, but the relative humidity performed less impact. In our study case, the PMV model could not well applied to Songkhla’s people as it predicted the neutral temperature one and a half degree colder than the actual, and underestimated the hyper-sensitivity of the thermal sensation to the temperature.