Spatial diversity and total area of thermal-humid regions have been assessed and, in addition, climatic water balance values have been calculated, employing specific time-frames up until the year 2020. The latter calculations have been performed taking into account temperature averages for the period 1971-2000, and constant precipitation. In order to designate thermal-humid regions the Daunbenmiere method has been used (version modified by Cherszkowicz) in which thermal conditions are determined on the basis of effective temperature sums ≥10.0ºC, while pluvial conditions are determined based on the hydrothermal coefficient (K=10P/t) for the period from June until August where P signifies sums of precipitation and t daily sums of air temperature values. The climatic water balance was calculated as the difference between precipitation sums and sums of potential evaporation calculated using the Thornthwaite method. A systematic increase of the area of temperate warm and warm regions has been identified (from 62% in the period 1971-2000 to 88% for values estimated for 2000, 98% for values estimated for 2010, and 100% for 2015 and 2020). Meanwhile, a systematic increase in the area of temperate dry regions has been observed (20% of Poland in 1971-2000, 45% for values estimated for 2010, and 48% for values estimated for 2015 and 2020). The values of climatic water balance have decreased in the Nizina Wielkopolska from -160 mm (1971-2000) to -220 mm (for values estimated for 2015).