Sartrouville's winters are typically cold and unpredictable, with temperatures often dropping below freezing in January and February. As the seasons shift towards spring, temperatures slowly rise, reaching averages of around 7-8°C by March and April. Summer brings mild warmth, with highs occasionally soaring above 30°C in June and July, but also experiencing cooler days. Autumn is generally cool and temperate, with temperatures gradually decreasing from September to November before dropping again into winter. December's temperature fluctuations are similar to February's, indicating a consistent pattern of cold winters.