The goal of this paper is to determine the state of extreme air temperature in Republic of Srpska and to establish their thresholds as the limits of unsuitability of the climate. The air temperature much above and much below was investigated. The spatial distribution of minimal air temperatures in Republic of Srpska during the studied period 2006-2010 shows the meridian, parallel and altitude regularity. The average annual maximums increase slowly from the north towards the south and insignificantly from the west towards the east of Republic of Srpska.