December weather forecast
Rio das Ostras, Brazil

December, the first month of the summer in Rio das Ostras, is still a warm month, with an average temperature varying between 22.2°C (72°F) and 27.5°C (81.5°F).

Temperature

At the onset of December, Rio das Ostras records an average high-temperature of a still moderately hot 27.5°C (81.5°F), showing little deviation from the preceding month. In December, the recorded average low-temperature is a pleasant 22.2°C (72°F).

Heat index

The heat index value during December is evaluated at a tropical 31°C (87.8°F). Fatigue might occur with continuous exposure and activity, potentially causing heat cramps.
Heat index evaluations are typically in the context of light winds and shaded environments. Direct sunlight can potentially boost the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', is what the temperature feels like to the human body when the air temperature is combined with the relative humidity. The influence of weather is personal, differing among a variety of individuals based on differences in body mass, stature, and the level of physical activity. Being aware that direct sunlight can impact the felt heat might mean an increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are quite important for children. Children typically face more danger than adults as their sweat production is usually lower. Additionally, the bigger skin surface compared to their small size and the increased heat due to their activeness exacerbate the risk.

Humidity

November and December, with an average relative humidity of 84%, are the most humid months.

Rainfall

In Rio das Ostras, in December, it is raining for 19.9 days, with typically 100mm (3.94") of accumulated precipitation. Throughout the year, in Rio das Ostras, there are 179.7 rainfall days, and 674mm (26.54") of precipitation is accumulated.

Sea temperature

In Rio das Ostras, in December, the average water temperature is 24.1°C (75.4°F).
Note: Think about diving into 24.1°C (75.4°F) waters. Factors like your sensitivity to cold, the brightness of the sun, wind conditions, and the day's warmth play a role. For reference, Olympic swimming competitions use waters between 25°C (77°F) and 28°C (82.4°F).

Daylight

The month with the longest days in Rio das Ostras is December, with an average of 13h and 30min of daylight.
On the first day of the month, sunrise is at 04:54 and sunset at 18:19. On the last day of December, sunrise is at 05:06 and sunset at 18:35 -03.

Sunshine

The average sunshine in December in Rio das Ostras is 8.8h.

UV index

In Rio das Ostras, the average daily maximum UV index in December is 6. A UV Index value of 6 to 7 symbolizes a high health risk from unprotected exposure to Sun's UV rays for the ordinary person.
Note: A typical high UV index of 6 in December suggests the following recommendations:
Use protective steps and abide by sun safety guidelines. Safeguarding against skin and eye harm is necessary. Seek shade and limit direct sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation. Keep in mind that shade structures like parasols or canopies do not offer complete sun protection. Sun-protective clothing, a long-sleeved shirt and pants, a wide-brimmed hat, and UVA and UVB-blocking sunglasses are particularly helpful in blocking UV radiation's harmful effects. Caution! The Sun's UV intensity grows with reflections off sand and water.