Grenoble's winters are cold and unpredictable, with temperatures often dropping below freezing in January and February, but occasionally rising into the mid-teens. Spring brings gradual warming, with March and April temperatures fluctuating between chilly mornings and balmy afternoons. Summers are warm to hot, with June and July averaging around 20°C, while September cools down slightly before October's temperature swings return. Autumn and winter months see a mix of mild and cold days, with November and December often being quite chilly.