The main purpose of this paper is to summarise the key findings of ASHRAE research project RP-702, a field investigation of indoor climates and occupant comfort in 12 air conditioned office buildings in Townsville, located in Australia's tropical north. The project replicates an earlier ASHRAE investigation in San Francisco (RP-462), the main purpose being to field-validate the ASHRAE comfort chart (Standard 55) in a tropical setting.