December weather forecast
Arco-Íris, Brazil

The first month of the summer, December, is still a warm month in Arco-Íris, Brazil, with an average temperature varying between 29.6°C (85.3°F) and 20.7°C (69.3°F).

Temperature

December's advent presents an average high-temperature of a warm 29.6°C (85.3°F), indicating a slight variation from the conditions of the previous month. The low-temperature averages to a pleasant 20.7°C (69.3°F) during the nights of December.

Heat index

Throughout December, the heat index is calculated to be a fiery hot 36°C (96.8°F). Exercise increased caution, heat cramps and heat exhaustion are potential hazards. Continuous activity could lead to heatstroke.
It is essential to grasp that the heat index's numbers are for shade and light wind settings. A rise in the heat index by 15 Fahrenheit (8 Celsius) degrees may result from direct sunlight exposure.
Note: The heat index, also known as 'felt air temperature' or 'apparent temperature', is achieved by amalgamating air temperature with the relative humidity readings. This impact is subjective, influenced by the person's physical activity and individual heat perception, affected by factors including wind, attire, and metabolic differences. Consider that direct sun exposure can intensify the felt heat, adding potentially 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are particularly relevant to babies and toddlers. Young ones often disregard the necessity to rest and hydrate. Thirst usually indicates advanced dehydration - hence, it is key to stay hydrated, particularly during ongoing physical activities.
To achieve cooling, the human body employs perspiration, relying on the subsequent evaporation of sweat. An upsurge in relative humidity affects normal body cooling mechanisms by slowing evaporation, hence reducing the rate at which the body cools and intensifying the perception of heat. When the body is unable to balance heat gain, its temperature elevates, which may induce thermal illnesses.

Humidity

In December, the average relative humidity is 79%.

Rainfall

In December, the rain falls for 25.5 days. Throughout December, 160mm (6.3") of precipitation is accumulated. In Arco-Íris, during the entire year, the rain falls for 193.5 days and collects up to 1136mm (44.72") of precipitation.

Daylight

With an average of 13h and 24min of daylight, December has the longest days of the year in Arco-Íris.
On the first day of the month, sunrise is at 05:30 and sunset at 18:52. On the last day of December, sunrise is at 05:41 and sunset at 19:08 -03.

Sunshine

In Arco-Íris, the average sunshine in December is 7.7h.

UV index

January through March, July through December, with an average maximum UV index of 6, are months with the highest UV index in Arco-Íris. A UV Index estimate of 6 to 7 represents a high health hazard from exposure to the Sun's UV radiation for the average person.
Note: The maximum daily UV index of 6 in December converts into the following recommendations:
Conform to measures and uphold sun safety traditions. Warding off skin and eye harm is necessary. Stay in the shade and limit direct sun exposure between 10 a.m. and 4 p.m., when UV radiation is at its strongest. Remember, however, that not all shade structures provide full sun protection. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes.