The article presents the changes in the values of average air temperature and its spatial diversity in the four seasons of the year (spring, summer, autumn, winter) in the years 1981–2010 compared with the 1971–2000 period. In the 1981–2010 period (the new climate normal currently in force) the largest increase in air temperature expressed in the average area value occurred in summer and reached 0.5°C. In spring and autumn the increase in average air temperature was smaller and was 0.4°C and 0.3°C respectively; in winter average temperature did not change compared with the previous climate normal.