Seasonal Variability of Fire Weather Index (FWI) Across Italy (2007–2024): A Reproducible Climate-Driven Assessment Framework

Wildfires are an increasing environmental and civil protection challenge across Southern Europe under intensifying climate variability and extreme heat conditions. This study presents a reproducible, climate-informed framework for analysing seasonal fire weather variability across Italy using the Canadian Fire Weather Index (FWI) system. The work was conducted during a Short-Term Scientific Mission funded by the NERO COST Action CA22164 at the University of Milan in September 2025. A harmonised Seasonal FWI dataset for Italy covering 2007–2024 was developed using Copernicus Climate Data Store products, Climate Data Operators (CDO), and R-based statistical workflows. Seasonal FWI metrics were spatially aggregated across 35 Italian ecoregions to evaluate temporal variability and regional fire danger patterns. Results reveal pronounced interannual variability, with mean FWI values ranging from approximately 16 in 2020 to 24 in 2016. Although no statistically significant monotonic trend was detected during 2007–2024, seasonal FWI values consistently exceeded the historical 1970–2000 baseline (~10–15), indicating a shift towards a higher fire danger regime. Figures illustrate the analysed ecoregions, regional burned area trends, and relationships between mean seasonal FWI and burned area. The openly available dataset and reproducible workflow provide a foundation for future climate-informed fire danger assessment and civil protection decision-support systems.