Winters in Cachan are cool and temperamental, with temperatures often dropping below freezing point but sometimes rising to mild highs. Spring arrives slowly, with March and April temperatures gradually warming up to averages around 8°C, but still experiencing occasional chilly days. Summer brings warm and stable conditions, with July and August being the warmest months, averaging around 19°C. Autumn is characterized by a steady decline in temperature, with September and October experiencing mild highs but also cool lows. Decembers and Januarys are essentially identical in their cold and unpredictable nature, with temperatures often fluctuating between freezing point and mild highs.