Winters in Upminster are cool and occasionally chilly, with January averaging a low of around 4°C and temperatures often dropping below freezing. February is similar but slightly warmer on average. As the season progresses into spring, temperatures gradually rise, reaching averages of around 7-11°C by May. Summer months see more stable warmth, with July typically being the warmest month, averaging around 18°C. Autumn brings a return to cooler temperatures, with November and December averaging around 7-8°C.