Quantifying climatic suitability for tourism in Southwest Indian Ocean Tropical Islands: Applying the Holiday Climate Index to Réunion Island.

Climate is a key resource for tourists and tourism providers. Varied approaches to quantifying climate resources for tourism have been developed in the last 40 years, computing indices from a range of meteorological variables to measure the comparative climatic suitability of different destinations through time. This study provides the first application of a tourism climate index in the tropical southwest Indian Ocean, applying the recently developed Holiday Climate Index (HCI) for Réunion Island. The suitability of this index is evaluated for the case of this French department, with a particular focus on air conditioning availability in tourism accommodation establishments as this index excludes night-time thermal comfort. Both iterations of the HCI (HCI and HCI) are computed with meteorological data from Roland Garros Airport for the period 1991-2020, exploring monthly, annual, and seasonal climatic suitability. Mean monthly HCI scores reveal considerable seasonality in climatic suitability for tourism on the island with scores ranging from 89.3 ('excellent') to 36.9 ('marginal') for the HCI and 85.0 ('excellent') to 27.5 ('unacceptable') for the HCI, with more favourable scores calculated for July and August, displaying a clear austral winter peak seasonal classification. Over the 30-year period, there is no statically significant change in mean annual climatic suitability, and at a monthly scale, only one month of the year for each index displays statistically significant trends. These results are important in informing tourism strategies for the island to maximise visitor satisfaction through targeting advertising more deliberately for peak touristic climate suitability during the winter months.