Atibaia's climate is mild, with temperatures gradually warming up in the summer months. From March to May, temperatures are relatively cool, ranging from 2-30°C, with averages around 18-23°C. The warmest period starts in June and extends through August, with highs occasionally reaching 33°C, but averages staying around 16-18°C. Summer proper brings hot afternoons, peaking at 37°C in September, while still maintaining cooler nights. As the year winds down, temperatures decrease slightly, returning to more moderate levels by December.