Winters in Ulm are cold and variable, with temperatures often dropping below freezing but occasionally rising into the mid-teens. Spring is a gradual warming period, with temperatures slowly increasing over several weeks before stabilizing around 10°C by May. Summers are warm to hot, with temperatures frequently reaching the high twenties during July and August. Autumn is mild, with temperatures cooling gradually from September onwards, though still often above freezing in October and November. Frosts return in December, ushering in another cold winter period.