Winters in Biel/Bienne are cold, with temperatures frequently below freezing and occasional drops to as low as -27°C. Spring is a gradual warming period, with temperatures slowly rising from around freezing in March to average highs of 17°C by June. Summer months bring mild temperatures, rarely dropping below 4°C at night and sometimes reaching up to 32°C during the day. Autumn is generally cooler than summer, with temperatures gradually decreasing over the course of the season, before cold winter conditions return.