Winters in Harrow are typically cool and unpredictable, with temperatures fluctuating between freezing cold and mild. January is the coldest month, averaging around 4°C, while February sees a slight improvement in temperature. As spring approaches, March and April bring moderate temperatures, ranging from -4°C to 17°C, but still susceptible to chilly days. Summer months of June to August are warm, with July being the warmest, often reaching highs of over 30°C, but also experiencing cooler mornings. Autumn brings a return to milder temperatures in September and October, before cooling down again towards winter.