Itanhaem's climate is characterized by mild winters and hot, humid summers. The coldest months are July and August, with average temperatures ranging from 4-19°C, while the warmest months are January to February, with temperatures often reaching up to 36°C. Spring (September to November) brings pleasant temperatures around 20°C, while autumn (March to May) is slightly cooler, averaging around 18°C. Summer's peak heat usually occurs in December and January, with temperatures frequently soaring above 30°C.