Pico Rivera's winters are mild, with temperatures ranging from around 2-30°C in January and December. As spring approaches, temperatures gradually rise, reaching an average high of 17-22°C by April and May. Summer months bring warmer days, with highs averaging 25-28°C in July and August, but cooler nights still occur. Autumn brings a slight drop in temperature, with highs ranging from 12-19°C from September to November.