On the grounds of the values of the day and night Tmax and Tmin recorded in the period from 1989 to 1998, the thermal conditions of north-eastern Poland were characterised. The values Tmax and Tmin in the area of the particular types and macrotypes of circulation were determined (acc. to Osuchowska-Klein), which was presented in the form of average values of the variable mentioned above for January and July and illustrated by means of a special schedule. The background for the considerations was constituted by observations in the form of the number of days with the presence of the particular macrotypes in the analysis. The analyses demonstrated explicitly warming or cool-ing influence of the circulation according to the movement direction of the mass of air against the values of Tmax and Tmin both in January and July, and also a partially cooling effect produced by the mass of air of cyclonal origin.