Winters in Hyvinkaa are long and cold, with temperatures often dropping below -20°C in January and February. Spring brings gradual warming, with April's average temperature around 4°C marking a significant increase in warmth. Summer is mild to warm, with July being the warmest month averaging around 21°C. Autumn sees a return to cooler temperatures, although not as cold as winter, with October's average temperature around 8°C.