Ground temperature (GT) data have been collected by A. Kholodov for the Thermal State of Permafrost (TSP)/Global Terrestrial Network for Permafrost (GTN‐P) programme at 12 sites in Siberia, with a main focus in eastern Siberian Kolyma Lowlands (9 Sites). Two sites are located on the Bykovsky peinsula in the Arctic at the Eastern outflow of the Lena River Delta, and in Central Yakutia North of the city of Yakutsk. Field work, station installation and data read-out and the processing to specific temporal averages has been conducted by Alexander Kholodov and Vladimir Romanovsky. The data presented here are the Mean Annual Ground Temperatures (MAGT), calculated from daily data as processed by A. Kholodov. Mareike Wieczorek calculated the MAGT time series, which were only created if not more than one complete month and not more than 20% overall values were missing in a dataset. Data are available from various depth at 0 cm, 10 cm, 20 cm, 25 cm, 40 cm, 50 cm, 300 cm, 400 cm, 500 cm, 1000 cm, 1500 cm, 2000, but not all sites have values at all depths.