This dataset provides chironomid abundance data for a Mid Weichselian sediment sequence retrieved from the Reichwalde mine situated in the Niederlausitz area (Germany) in 1999. Percent-abundances of individual chironomid taxa are presented against relative core depth (m). The lake deposit was encountered in an exposure of Weichselian sediments and was sampled using a box core. The material was dated to the early Mid Weichselian (ca 50ka BP) using 14C dating. A total of 18 samples were analysed for their chironomid content. Samples were taken from the box core, weighted, and subsequently processed in the laboratory (Vrije Universiteit Amsterdam, the Netherlands) using standard protocols - this involved 20min treatment with warm KOH (10%) and sieving over a 100µm mesh. Chironomid head capsules were subsequently handpicked from the residue, mounted on permanent microscope slides, and identified using the literature. This dataset provides chironomid percent-abundances relative to the total count of chironomid head capsules per sample. The chironomid dataset provides insight in the natural evolution of the lake ecosystem and was used to produce a chironomid-inferred July air temperature record.