Abstract. The development of tourist areas is highly dependent on their facilities and attractions. Nature-based tourism which relies on outdoor activities is significantly influenced by the level of comfort. Palabuhanratu is a tourism area known for its natural tourism, consisting of seaside beaches and marine activities, as well as the newly developed Ciletuh Geopark. The state of the climate in the area affects the comfort of the visiting tourists, particularly surface air temperature and humidity. These parameters are to be sensed directly by tourists participating in outdoor activities. The Temperature-Humidity Index (THI) is employed to illustrate the state of comfort, calculated from the previously mentioned two climate parameters. Spatiotemporal analysis based on GIS is used in this study, utilizing the ERA5 Reanalysis data in the period of 1991-2020. This study aims to determine the pattern of climate-based comfort level, in order to provide information on the possibly best visiting time. The month of May provides the highest THI values, indicating the worst possible time of the year to visit the area for outdoor activities. An analysis of the diurnal pattern of THI is also done to illustrate the sub-daily scale variation for additional consideration.

Keywords: THI, temperatur, relative humidity, tourism, climate comfort