Abstract
<title>Abstract</title> <p>Climate plays a fundamental role in determining tourism suitability, particularly in coastal regions where multiple tourism activities depend on favorable atmospheric conditions. This study presents the first comprehensive long-term assessment of tourism climate suitability along the Turkish Black Sea coast using the Holiday Climate Index (HCI). Daily ERA5-Land and ERA5 reanalysis datasets covering the 1950–2025 period were used to evaluate tourism climate conditions across eleven coastal provinces. To better represent the diverse tourism characteristics of the region, HCI:Coast and HCI:Urban were integrated through a novel weighted HCI:Combined approach based on the proportional distribution of coastal and urban grid cells within each province. Spatial distributions, seasonal patterns, temporal trends, and anomaly analyses were investigated using Mann–Kendall trend and Sen’s slope analyses. The results reveal pronounced spatial and seasonal variability in tourism climate suitability. Western and Central Black Sea provinces consistently exhibit higher and more stable HCI values than the Eastern Black Sea, where persistent humidity, cloud cover, and orographic precipitation continue to reduce climatic comfort. Summer and the peak tourism season provide the highest tourism suitability throughout the region; however, the strongest long-term improvements occur during spring and autumn. Trend and anomaly analyses indicate that climate change is extending climatically favorable conditions into the transitional seasons rather than substantially enhancing summer tourism conditions. Spatial changes are heterogeneous, with greater improvements observed in the western part of the region than in the east. The proposed HCI:Combined framework offers a practical methodology for evaluating regions where coastal and urban tourism coexist and may support climate-informed tourism planning and sustainable destination management under changing climatic conditions.</p>