January weather forecast
Rio de Janeiro, Brazil

Kicking off the year, January in Rio de Janeiro, Brazil is characterized by a tropically warm climate with high relative humidity. An impressive 102mm (4.02") of rainfall is usually recorded, making it a noticeably soggy month. Visitors and locals can experience heat with temperatures reaching up to 29.2°C (84.6°F). Conducive for beachgoers, the sea temperature this month averages at a comfortable 25.1°C (77.2°F). Notwithstanding the periodic rainfall, the city reveals its sunny side, presenting an average of 8.5 sunshine hours per day.

Temperature

The average high-temperature in Rio de Janeiro during January registers at a still moderately hot 29.2°C (84.6°F), maintaining a close resemblance to the previous month. Throughout January, Rio de Janeiro records an average temperature of 23.7°C (74.7°F) at night.

Heat index

For most parts of January, the heat index is estimated at a torrid 35°C (95°F). Take extra safety measures to prevent heat exhaustion and heat cramps. Heatstroke could follow lengthy activity.
Heat index guidelines indicate values are for light wind scenarios and shaded regions. Direct exposure to sunshine could lead to a heat index increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'real feel', is derived by integrating air temperature with the existing relative humidity to express the perceived warmth. The influence of weather can be personal, changing with an individual's body mass, height, and level of physical exertion. Be aware that direct exposure to sunlight increases heat impact and may raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular significance for children. Children often overlook the necessity for resting and fluid replenishment. Thirst is a late sign of dehydration - thus, it is critical to stay hydrated, especially during extended periods of physical activities.
Sweat evaporation plays a crucial role in cooling the human body, a process enabled by perspiration. When relative humidity increases, the body's capacity to evaporate heat decreases, leading to a heightened sense of warmth. Accumulating more heat than the body can dissipate leads to an uptick in body temperature, with potential heat stress consequences.

Humidity

In January, the average relative humidity in Rio de Janeiro is 79%.

Rainfall

In Rio de Janeiro, in January, it is raining for 19.8 days, with typically 102mm (4.02") of accumulated precipitation. Throughout the year, there are 192.5 rainfall days, and 812mm (31.97") of precipitation is accumulated.

Sea temperature

In Rio de Janeiro, in January, the average water temperature is 25.1°C (77.2°F).
Note: Water temperature ranging from 25°C (77°F) to 29°C (84.2°F) is seen as very warm and delightful by everyone. During these temperatures, water activities become enjoyable, without causing discomfort for extended periods.

Daylight

The average length of the day in January is 13h and 21min.
On the first day of the month, sunrise is at 05:10 and sunset at 18:41. On the last day of January, sunrise is at 05:31 and sunset at 18:40 -03.

Sunshine

The average sunshine in January in Rio de Janeiro is 8.5h.

UV index

The month with the highest UV index is January, with an average maximum UV index of 7. A UV Index estimate of 6 to 7 represents a high health risk from exposure to the Sun's UV rays for the ordinary person.
Note: An average UV index of 7 in January transforms into this advice:
Incorporate safeguards and honour sun safety principles. Protection from skin and eye damage is obligatory. Avoid exposure to the Sun and try to stay in the shade between 10 a.m. and 4 p.m., when UV radiation is most potent, but be aware that parasols or canopies may not offer full protection. Safeguard your eyes, ears, and face from sun rays with the aid of a wide-brim hat. Attention! UV strength is notably upped by the reflection of sand and water.