Winters in Vaasa are harsh and cold, with temperatures often dropping below -20°C and averaging around -6°C. Spring arrives slowly, with March typically being the first month to see temperatures rise above freezing, but still experiencing occasional frosts. Summer is mild and pleasant, with warmest months June and July averaging around 19°C, while September sees a return to autumnal chill. Autumn brings cool temperatures, with October and November often seeing nighttime lows below 0°C.