Inter-annual variability of air temperature, in particular, the alternation of cold and warm winters, is influenced, besides the global change and random weather variability, also by a climatic oscillation with the period about 7-8 years. This oscillation itself is very weak, its amplitude is less than half a degree Celsius. However, due to the recently discovered phenomenon of cross-scale interactions (M. Paluš, Phys. Rev. Lett. 112, 078702, 2014), this weak oscillation can cause significantly larger changes in short-term air temperature variability. The strongest effect has been observed in the boreal winter season. The difference between the winter mean temperatures in various parts of the 7-8-year cycle can exceed 4 degrees Celsius in central Europe. The large inter-annual changes of the seasonal temperature means can strongly influence economy, agriculture, tourism and human lives in general. It is important to understand physical mechanisms underlying these changes and find algorithms for their forecasting. This scientific result, obtained by the team from the Institute of Computer Science CAS, led by Dr. Paluš, in cooperation with scientists from the University of Wisconsin in Milwaukee, has been published in prestigious journal Geophysical Research Letters.