Winters in Mantes-la-Jolie are cool and variable, with temperatures often below freezing but occasionally rising into double digits. Spring is a gradual warming period, with temperatures slowly increasing over the months of March and April. Summer brings warm days, with highs sometimes reaching up to 30 degrees Celsius, but nighttime temperatures remain mild. Autumn is marked by a cooling trend, with temperatures dropping steadily from September through November, bringing a return to cooler winter conditions. Overall, temperature fluctuations are common throughout the year, with no distinct season lasting for an extended period.