Aulnay-sous-Bois experiences a moderate climate with distinct seasons. Winters are chilly, with temperatures often below freezing in January and February, but warming up slightly by March. Spring arrives slowly, with April and May bringing gradual increases in temperature, eventually reaching highs of 27°C in May. Summers are mild, with July and August averaging around 19°C, while September's temperatures begin to drop. As autumn sets in, October's cooler days give way to November's chill, mirroring the winter months' cold snaps.