The Fire Weather Index (FWI) is a numeric rating of fire intensity. It combines the Initial Spread Index (ISI) and the Build Up Index (BUI). It is suitable as a general index of fire danger. This is part of a larger dataset providing gridded field calculations from the Canadian Fire Weather Index System using weather forcings from the European Centre for Medium-range Weather Forecast (ECMWF) ERA-Interim reanalysis dataset (Di Giuseppe et al., 2016). The dataset has been developed through a collaboration between the Joint Research Centre and ECMWF under the umbrella of the Global Wildfires Information System (GWIS), a joint initiative of the GEO and the Copernicus Work Programs. The whole dataset consists of seven indices, each of which describes a different aspect of the effect that fuel moisture and wind have on fire ignition probability and its behavior, if started. The indices are called: Fine Fuel Moisture Code (FFMC), Duff Moisture Code (DMC), Drought Code (DC), Initial Spread Index (ISI), Build Up Index (BUI), Fire Weather Index (FWI) and Daily Severity Rating (DSR). For convenience, each index is archived separately. This dataset can be manipulated using the caliver R package (Vitolo et al. 2017a, b). File format: netcdf4 Coordinate system: World Geodetic System 1984 (WGS84) Longitude range: [-180, +180]