january is the hottest month of the year in rio de janeiro - this is a summer month, since summer in the southern hemisphere starts december 21st and ends march 20.

there is a maximum weather of 29 degrees celsius or 84 degrees fahrenheit, and a minimum of 23 degrees celsius or 73 fahrenheit.

the nighttime temperature stays at mid 20s - there is plenty of rainfall during the month of january, with an average rainfall of 137 mm, 13 wet days throughout the months and a relative humidity of 78%.

during this hot summer month, the evenings are much cooler due to heavy and rapid rains, making the temperature more comfortable.