This record provides the reproducibility package for the manuscript “Deployment-Consistent Multi-Horizon Solar Irradiance Forecasting: Skill Against Issue-Time-Constructible Strong Benchmarks.” The package contains the analytical code, executable Jupyter notebooks, processed multi-horizon forecasting tasks, frozen prediction artifacts, input and configuration manifests, checksum and integrity audits, reference tables and figures, and external-site validation materials for İzmir, Davos, Ouarzazate, and Tõravere. The package is designed to reproduce the benchmark construction, statistical inference, figures, tables, and four-site synthesis reported in the manuscript without retraining or retuning the forecasting models. The supplied prediction artifacts and processed datasets are checksum-audited and correspond to the frozen experimental configurations used in the study. Raw yearly NSRDB source files are not redistributed. The included processed and derived data artifacts originate from the National Solar Radiation Database (NSRDB) Meteosat product distributed by the U.S. National Renewable Energy Laboratory (NREL). Users should retain the appropriate NREL/NSRDB attribution when reusing or transforming these artifacts. Detailed reproduction instructions, software requirements, licensing conditions, provenance information, component-level checksums, and expected results are provided within the archive.