Winters in Parsippany-Troy Hills are typically cold, with temperatures often dropping below freezing and averaging around 2-1°C. As spring arrives, temperatures gradually warm up, reaching an average of 7°C by March and 12°C by April. Summer brings a warm and relatively stable climate, with July and August temperatures averaging around 25°C. Autumn is mild, with September temperatures similar to those in May, but cooling off again by October. Winters return, with temperatures dropping back down into the cold range by December.