Winters in Velletri are generally mild, with January averaging a cool 8°C and December averaging a chilly 10°C. Spring brings steady warming, with April and May temperatures rising to averages of 12°C and 17°C respectively. Summer is warm to hot, with July and August often reaching highs above 35°C, but also experiencing some cooler days around 16°C. Autumn sees a return to milder temperatures, with September averaging 22°C and November averaging 14°C. The temperature fluctuation throughout the year is relatively moderate, with no extreme lows or highs.