Vertical greenery systems have gained attention for enhancing the thermal efficiency of buildings, with notable success in tropical and Mediterranean climates. However, their impact in composite climates, where seasonal variations are pronounced, especially on the indoor comfort of naturally ventilated buildings, has been less explored. This study aims to bridge this knowledge gap through a targeted case-control experiment in Delhi, India, focusing on the monsoon season. The thermal behaviour of a building with a direct green facade is analysed and compared to that of a building with a conventional bare wall. This study, concentrating on both the wettest and hottest days of the monsoon season, reveals that green facades can lower indoor temperatures by up to 3 ℃ but also slightly elevate humidity levels, which compromises thermal comfort. However, the application of adaptive comfort standards, including ASHRAE-55 and the Indian Model for Adaptive Comfort (IMAC), indicates that green facades succeed in maintaining operative temperatures within a comfortable range. This investigation enriches our understanding of the dual effects of vertical greenery systems on temperature and humidity, offering a nuanced view of their potential to improve indoor environmental quality in composite climates. This highlights the complexities of integrating green facades in such climates and underscores their value and limitations in enhancing occupant comfort. Our findings pave the way for a more informed use of green facades, underscoring their strategic importance in architectural design for diverse climates.