Day-ahead solar irradiance forecasts for Dnipro (2025): synchronized data, code and calculation results

A processed dataset of 3933 daylight hourly records comparing 24-hour-ahead ECMWF IFS 0.25°, GFS Global and ICON-EU global horizontal irradiance forecasts with EUMETSAT CM SAF SARAH-3 in Dnipro, Ukraine, during 2025. The archive includes synchronized hourly data, reproducible Python code, calculation results, figures, a data dictionary and source attribution. Evaluation includes a chronological training/test split and 5000 daily-block bootstrap resamples. CSV data and calculation results: CC BY 4.0. Original software: MIT. No ground measurements or photovoltaic electrical power data are included.