Winters in Casalnuovo di Napoli are mild, with temperatures ranging from -2 to 16°C, averaging around 9°C. Spring brings gradual warming, with March and April temperatures reaching as high as 23-28°C on average. Summers are warm, with July and August often seeing highs of 36-39°C, but temperatures rarely drop below 17-16°C. Autumn is mild, with September's highs averaging around 23°C and October's dropping to 6-8°C. Frosts are rare during winter months, while occasional heatwaves can occur in the summer.