Understanding local patterns and large scale processes in past climate necessitates detailed network of temperature reconstructions. In this study, a merged temperature inference model using fossil chironomid (Diptera: Chironomidae) datasets from Finland and Poland was constructed to fill the lack of an applicable training set for East European sites. The developed weighted averaging-partial least squares (WA-PLS) inference model showed favorable performance statistics suggesting that the model can be useful for downcore reconstructions. The combined calibration model includes 212 sites, 142 taxa and a temperature gradient of 11.3-20.1 °C. The 2component WA-PLS model has a cross-validated coefficient of determination of 0.88 and a root mean squared prediction error of 0.88 °C. We tested the new East European temperature transfer function in chironomid stratigraphies from a Finnish high-resolution short-core sediment record and a Polish paleolake (Żabieniec) covering the past ~20,000 yr. In the Finnish site, the chironomidinferred temperatures correlated closely with the observed instrumental temperatures showing improved accuracy compared to estimates by the original Finnish calibration model. In addition, the long-core reconstruction from the Polish site showed logical results in its general trends compared to existing knowledge on the past regional climate trends, however, with distinct differences when compared with hemispheric climate oscillations. Hence, based on these findings, the new temperature model will enable more detailed examination of long-term temperature variability in Eastern Europe, and consequently reliable identification of local and regional climate variability of the past.