Large-scale atmospheric circulation is a critical factor that controls the surface climatic conditions of a specific region. The scope of this work is to examine this relationship for different climatic regions over Greece and provide a detailed descriptive statistical analysis for multiple parameters related to heat and drought. The atmospheric circulation patterns are provided using a neural network approach and the surface climatic parameters are extracted from 17 surface meteorological stations for a 30-year period. In detail, for each circulation pattern the maximum and minimum temperature, the diurnal temperature range along with the precipitation amount are assessed. The 32 identified regimes describe effectively the large-scale atmospheric circulation and they are found to affect significantly the climatic parameters variability. Interesting statistical aspects are extracted for each climatic region and specific atmospheric circulation patterns are found to be associated with extreme heat and drought in the region. The persistence of atmospheric circulation is examined and associated with unusual episodes. The quantification of the large-scale effect on climatic parameters anomalies is demonstrated and is also discussed in terms of the effect of local topography and urbanization in each site.