Daily hindcasted water temperature and model outputs for 46 sites in the Nechako Watershed

This dataset provides long-term daily hindcast simulations of water temperature for 46 sites across the Nechako Watershed in British Columbia, Canada, using 3-parameter and 5-parameter forms of the Air2Stream model. The hindcast simulations cover the period from 1940 to 2024 using the ERA5 dataset and from 1950 to 2024 using the ERA5-Land dataset. The dataset was generated using the Air2Stream model, which was calibrated with observed water temperature data from the Northern Hydrometeorology Group (NHG), British Columbia Hydrometric data (BCH), Rio Tinto Alcan (RTA), and Water Survey of Canada (WSC), as well as meteorological inputs from the ERA5 and ERA5-Land reanalysis products. The model exhibits high performance, with Root Mean Square Error (RMSE) values consistently below 1.5 °C for all stations.This dataset includes three XLSX files. The first file, "1-Stations list.xlsx," shows the name, coordinates, and provider for all 46 stations. The fields "No." (station number) and "Station Name" are used in the second and third files.The second file, "2-Calibration metrics and parameters.xlsx," has four worksheets, organized into two model forms and two input datasets. In each worksheet, the calibration and validation metrics are presented. Moreover, the calibrated parameters are presented. The calibrated parameters are based on the following equations for the Air2Stream model forms: Air2Stream form Equation 5-parameter dTw/dt = a1 + a2Ta − a3Tw + a6 × cos[2π(t/ty − a7)] 3-parameter dTw/dt = a1 + a2Ta − a3Tw The third file, "3-Air2Stream simulations.xlsx," also has four worksheets, similar to those in the second file. In each worksheet, the header shows the station number and station name. Each worksheet shows the date (YYYY, MM, DD) in the first three columns, followed by the hindcast simulations in the remaining 46 columns.