Winters in Trollhattan are cold and relatively uniform, with temperatures ranging from around -9°C to 8°C on average. Spring brings a gradual warming trend, with March often seeing the first hints of warmth, followed by significant temperature increases in April and May. Summer is mild to warm, with July usually being the warmest month, but temperatures remain within a comfortable range. Autumn sees a return to cooler temperatures, with September and October experiencing average highs around 13°C and 10°C respectively. The coldest months are January, November, and December, while the warmer months are May through August.