This dataset contains hourly average temperature data interpolated from station observations using Gaussian copula method. The data are provided in NetCDF4 format, covering the period 1999–2002. The dataset is part of a larger dataset spanning 1991–2024, based on observations from 577 weather stations. Of these stations, 123 have less than 10% missing data over the full period, but all available information from all stations was used to produce the interpolated hourly dataset. Original station data are available at: https://opendata.dwd.de/climate_environment/CDC/observations_germany/climate/hourly/air_temperature The dataset includes: Variables: Hourly temperature (°C) Spatial coverage: Germany Temporal coverage: 1 January 1999 – 31 December 2002, hourly resolution Processing: Observations were interpolated using Gaussian copula-based method. Notes: This is Part 3 of the full 1991–2024 dataset. For the next time period (2003–2006), see the corresponding Zenodo record: 10.5281/zenodo.18833741 Each file is self-contained and includes all variables, time steps, and metadata.