Winters in Vasteras are cold and snowy, with temperatures often below freezing, averaging around -4°C in February, the coldest month. Spring brings gradual warming, with March and April temperatures rising to an average of around 3-4°C. Summer is mild and pleasant, with July being the warmest month, averaging around 20°C, while August and June are also warm, but slightly cooler. Autumn is a transitional season, with temperatures decreasing gradually from September to November, bringing back colder winter conditions by December.