Banja Luka's winters are cold and snowy, with January averaging just 3°C, while February is slightly warmer. As spring arrives in March, temperatures rise steadily, reaching averages of 7°C by the end of the month. Summer brings warmth, with June and July often seeing highs above 30°C, but August cools slightly. Autumn brings a return to cooler temperatures, with October averaging around 9°C before dropping again into winter.