Winters in Letchworth are typically cold and unpredictable, with temperatures fluctuating wildly between -7°C and 12°C. As the season progresses, temperatures gradually warm up, but even in March, the coldest month of the year, highs can only reach around 22°C on average. Spring brings a more consistent rise in temperature, with May and June averaging around 10-16°C. Summer is warm and pleasant, with July often reaching highs above 29°C, but August and September are slightly cooler. Autumn is marked by a gradual decline in temperature, with October's highs barely scraping 20°C on average.