Gap filled air temperature time-series for Yakutia, Chukotka and Magadan Oblast from 01-01-1966 to 30-09-2025

This dataset provides a gap-filled, quality-controlled record of daily air temperature for meteorological stations in north-eastern Eurasia - Yakutia, Magadan Oblast and Chukotka, covering 167 stations over the period 01-01-1966 to 30-09-2025. For each station it includes daily mean temperature and daily minimum/maximum (diurnal extremes), with observed values preserved and missing values reconstructed. The base observations were compiled and quality-controlled from open meteorological archives meteo.ru, rp5.ru, pogodaiklimate.ru. Gaps were filled station-by-station using neighbouring stations and an ensemble of statistical and machine-learning models (GAM, OLS+AR, and gradient-boosting/recurrent-network methods), with record-length-adaptive complexity, expanding-window cross-validation, and bias/trend corrections. Each estimate is flagged by origin (observed vs. modelled) and by the model(s) used. The deposit contains: the gap-filled dataset, the per-station validation/diagnostics table, and the full R reconstruction code. See the included README.md for data format, required columns, methodology, validation metrics, and reproducibility notes.