Rio de Janeiro
Brazil
Long-term weather forecast
Long-term weather forecast

January weather forecast and climate
Rio de Janeiro, Brazil

January, the same as December, is a moderately hot summer month in Rio de Janeiro, Brazil, with average temperature varying between 29.2°C (84.6°F) and 23.7°C (74.7°F).

Temperature

In Rio de Janeiro, the average high-temperature is relatively the same as in December - a still warm 29.2°C (84.6°F). The average low-temperature, in January, is 23.7°C (74.7°F).

Heat index

The average heat index is evaluated at a very hot 35.1°C (95.2°F). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
Note that heat index values are valued for light wind and location in the shade. With the exposure to direct sunlight, the heat index may be increased by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel', 'felt air temperature', 'apparent temperature', or 'feels like', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. Additional factors like wind, metabolic differences, pregnancy, and activity influence one's weather impression. Be aware that direct exposure to sunlight increases heat impact, and may raise the heat index additionally, by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Children are often less aware of the need to rest and re-hydrate. Thirst is a late sign of dehydration - it is vital to remain hydrated, particularly during prolonged physical activities.
Perspiration is the human body's physiological response to high temperatures and is an attempt to lower body temperature through evaporation of sweat. High relative humidity reduces the evaporation rate, resulting in a lower heat removal rate from the body, causing the perception of being overheated. When heat gain exceeds the level the body can remove, body temperature begins to rise, and heat-related illnesses and disorders may develop.

Humidity

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

Rainfall

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

Sea temperature

In Rio de Janeiro, the average seawater temperature in January is 25.1°C (77.2°F).
Note: For any water activity, surface water temperatures between 25°C (77°F) and 29°C (84.2°F) are considered as excellent and extremely pleasant for lengthened periods.

Daylight

In Rio de Janeiro, the average length of the day in January is 13.4h.

Sunshine

In Rio de Janeiro, the average sunshine is 8.5h.

UV index

January is the month with the highest UV index, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high threat to health from unprotected exposure to the Sun's UV rays for the average person.
Note: The average daily UV index of 7 transform into the following instructions:
Take precautions against overexposure. Protection against sun damage is needed. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. A wide-brim hat offers excellent sun protection for eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. Caution! The reflection of sand and water significantly increases the intensity of the Sun's UV radiation.

What is the temperature in January in Rio de Janeiro?

The average high-temperature, in January, is 29.2°C (84.6°F), while the average low-temperature is 23.7°C (74.7°F). The average heat index (a.k.a. 'felt air temperature', 'real feel'), that combines air temperature and relative humidity, in January is appraised at 35.1°C (95.2°F).

What is the average humidity in January in Rio de Janeiro?

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

How many days does it rain in January in Rio de Janeiro?

In Rio de Janeiro, Brazil, during January, the rain falls for 19.8 days and regularly aggregates up to 102mm (4.02") of precipitation.

How warm is the water in January in Rio de Janeiro?

In Rio de Janeiro, the average seawater temperature in January is 25.1°C (77.2°F). For swimming, diving, and other water activities, temperatures between 25°C (77°F) and 29°C (84.2°F) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

What is the average length of the day in January in Rio de Janeiro?

In January, the average length of the day in Rio de Janeiro is 13.4h.

How many hours of sunshine does Rio de Janeiro have in January?

In Rio de Janeiro, Brazil, the average sunshine in January is 8.5h.

When is the highest UV index in Rio de Janeiro?

The month with the highest UV index in Rio de Janeiro, Brazil, is January, with an average maximum UV index of 7.

How high is the UV index in January in Rio de Janeiro?

In Rio de Janeiro, Brazil, the average daily maximum UV index in January is 7. A UV Index reading of 6 to 7 represents a high health risk from unprotected exposure to the UV radiation.
Average temperature in January - Rio de Janeiro, Brazil
  • Average high temperature in January: 29.2°C

The warmest month (with the highest average high temperature) is February (29.7°C).
The month with the lowest average high temperature is July (24°C).

  • Average low temperature in January: 23.7°C

The month with the highest average low temperature is January (23.7°C).
The coldest month (with the lowest average low temperature) is August (18.5°C).

Average humidity in January - Rio de Janeiro, Brazil
  • Average humidity in January: 79%

The month with the highest relative humidity is November (82%).
The month with the lowest relative humidity is August (76%).

Average rainfall in January - Rio de Janeiro, Brazil
  • Average rainfall in January: 102mm

The wettest month (with the highest rainfall) is November (119mm).
The driest month (with the least rainfall) is June (29mm).

Average rainfall days in January - Rio de Janeiro, Brazil
  • Average rainfall days in January: 19.8 days

The month with the highest number of rainy days is March (22.7 days).
The month with the least rainy days is July (9.3 days).

Average sea temperature in January - Rio de Janeiro, Brazil
  • Average sea temperature in January: 25.1°C

The best month for swimming (with the highest average sea temperature) is March (25.8°C).
The coldest month (with the lowest average sea temperature) is September (21.6°C).

Average daylight in January / Average sunshine in January - Rio de Janeiro, Brazil
  • Average daylight in January: 13.4h

The month with the longest days is December (Average daylight: 13.5h).
The month with the shortest days is June (Average daylight: 10.7h).

  • Average sunshine in January: 8.5h

The month with the most sunshine is February (Average sunshine: 8.8h).
The month with the least sunshine is October (Average sunshine: 7.5h).

Average UV index in January - Rio de Janeiro, Brazil
  • Average UV index in January: 7

The month with the highest UV index is January (UV index 7).
The month with the lowest UV index is September (UV index 5).