This article presents a brand new pluvio-thermal regionalization of the Polish climate for two separate periods: 1971-2000 and 1991-2000. The method employed in this study is an old one, and was devised and tested in 1971 by a research group headed by professor Cherszkowicz, who used data for the period 1931-1960. Several comparisons have been performed in this study. The results indicate that the overall area of temperate-cool region (temperature sum ≥10.0˚C, 2000-2400˚C) has been decreasing in subsequent periods (39, 37 and 22% respectively). At the same time the area of the temperate-warm region (temperature sum ≥10.0˚C, 2400-2800˚C) has been increasing (61, 62 and 78% respectively). There has been a clear increase for the area of the temperate-dry region, from 13% (1931-1960) to 20% (1971-2000) and up to 58% in the last decade of the twentieth century. The aforementioned regions have been devised on the basis of the Sielianinow hydro-thermal coefficient within the value range of 1.0-1.3.