December weather forecastNilópolis, Brazil

Weather in December

December, the first month of the summer in Nilópolis, is also a moderately hot month, with temperature in the range of an average low of 21.3°C (70.3°F) and an average high of 29.3°C (84.7°F).

Temperature

The arrival of December coincides with an average high-temperature of a still warm 29.3°C (84.7°F), indicating a minimal shift from November's 27.2°C (81°F). Nilópolis records an average low of 21.3°C (70.3°F) throughout the nights in December.

Heat index

December's heat index is calculated to be a sweltering 36°C (96.8°F). Ensure extra safety steps, heat exhaustion and heat cramps are likely. Long activity might lead to heatstroke.
One should consider that heat index numbers are for shaded settings and light wind. If exposed to direct sunlight, the heat index could climb by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'felt air temperature', combines both the air temperature and the humidity level to give a perceived human temperature. One's perception of temperature is subjective, varying based on their activity and individual heat perception, influenced by factors like wind, clothing, and metabolic variations. Direct sunlight can potentially raise the heat index by 15 Fahrenheit (8 Celsius) degrees, so it's crucial to consider. Heat index values are quite important for babies and toddlers. Children frequently underestimate the importance of resting and drinking fluids. Thirst is a symptom of advanced dehydration - hence the need to hydrate regularly, especially during protracted physical exercises.
The body's natural response to excessive warmth is perspiration, as it allows for cooling through sweat evaporation. In the presence of elevated relative humidity, the evaporation rate decreases. This reduction leads to increased body heat retention compared to conditions of dry air. Heat-related challenges, like dehydration, can be anticipated when body heat isn't managed effectively.

Humidity

The average relative humidity in December is 82%.

Rainfall

In December, the rain falls for 25.7 days. Throughout December, 134mm (5.28") of precipitation is accumulated. Throughout the year, there are 220.6 rainfall days, and 991mm (39.02") of precipitation is accumulated.

Daylight

With an average of 13h and 30min of daylight, December has the longest days of the year.
On the first day of December, sunrise is at 04:59 and sunset at 18:25. On the last day of the month, sunrise is at 05:11 and sunset at 18:42 -03.

Sunshine

The average sunshine in December is 7.5h.

UV index

December is the month with the highest UV index in Nilópolis, with an average maximum UV index of 7. A UV Index of 6 to 7 symbolizes a high health hazard from unprotected exposure to Sun's UV rays for the average person.
Note: In December, the maximum UV index of 7 suggests this advice:
Eschew overexposure. Those with light skin may suffer burns in fewer than 20 minutes. Minimize exposure to direct sunlight and seek shade from 10 a.m. to 4 p.m., when UV radiation is most intense, but remember that shade structures may not offer complete protection. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.