In total, 111 modern surface lake sediments were analysed on their pollen spectra. Field work was conducted between 2006 and 2011 during joint Russian-German expeditions in the lowlands of Arctic Siberia. At each lake centre, the upper 2 cm of sediment were retrieved using a bottom sampler or gravity corer. The distance between the westernmost sampling sites in the southern Taymyr region and the easternmost sites in the Kolyma lowlands is roughly 1800 km. The longest north-to-south transect, in the Lena region, is approximately 200 km long. The included modern July temperatures at the sites range between 7.5 and 18.5°C (based on MODIS satellite imagery from the years between 2007 and 2010, Duguay et al., 2012, doi:10.1594/PANGAEA.775962). Annual precipitation at the sites ranges between 114 to 315 mm/year (WORLDCLIM, Hijmans et al., 2005, doi:10.1002/joc.1276).