Winters in Kalmar, Sweden are cold and unpredictable, with January temperatures averaging around 1°C, fluctuating between -10°C and 7°C. February is similarly chilly, with an average temperature of 0°C. Spring arrives slowly, with March temperatures gradually warming up to an average of 3°C, while April sees a more noticeable rise to 5°C on average. Summer brings warmth, with June through August averaging around 17-20°C, but September and October see a return to cooler temperatures, ranging from 7-16°C. By November and December, the cold returns, with average temperatures dipping back down to around 2°C.