December weather forecast
Manaus, Brazil

December rounds out the year with weather trends consistent with those observed in November. High temperatures prevail at 31.3°C (88.3°F) and heavy showers are characteristic of the tropical wet season. Even though December has fewer daylight hours, it possesses a unique charm. With prolonged rainfall, the Amazon Rainforest becomes a vibrant ecosystem teeming with life, a spectacle to behold for visitors and nature lovers alike.

Temperature

With the onset of December, the average high-temperature registers at a still tropical 31.3°C (88.3°F), subtly different from November's 32.1°C (89.8°F). In Manaus, an average nighttime temperature of 23.5°C (74.3°F) is expected during December.

Heat index

December's heat index is calculated to be a blistering 44°C (111.2°F). Watchful: Heat cramps and heat exhaustion are predicted. Continued exertion could lead to heatstroke.
Be aware that heat index ratings are designed for shaded locations and minor breezes. Under direct sunshine, the heat index values might be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'felt air temperature', is calculated by taking the relative humidity value for a specific location and factoring it into the air temperature reading. The impact of temperature is individual, as people's perception of weather may change based on their body mass, height, and physical activity. Do note, being directly under sun rays can amplify the heat you feel, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. Young children are more at risk than adults since they tend to sweat less. Moreover, their large skin surface in proportion to their small bodies and the high heat production due to their activities contribute to their vulnerability.
In the face of high temperatures, the human body's reflex is to perspire, leveraging sweat evaporation for cooling. With higher relative humidity, the rate of evaporation is reduced, resulting in increased heat retention in the body compared to drier air. When body temperature rises due to excess heat gain beyond its removal capability, one might experience heat-related disorders.

Humidity

In December, the average relative humidity in Manaus, Brazil, is 85%.

Rainfall

In Manaus, in December, during 16 rainfall days, 220mm (8.66") of precipitation is typically accumulated. In Manaus, during the entire year, the rain falls for 160 days and collects up to 2307mm (90.83") of precipitation.

Daylight

With an average of 12h and 18min of daylight, December has the longest days of the year.
On the first day of December in Manaus, Brazil, sunrise is at 05:40 and sunset at 17:58. On the last day of the month, sunrise is at 05:54 and sunset at 18:12 -04.

Sunshine

In December, the average sunshine in Manaus is 4.2h.

UV index

January through May, August through December, with an average maximum UV index of 12, are months with the highest UV index. A UV Index reading of 11, and higher, represents an excessive health risk from exposure to the Sun's UV rays for the average person.
Note: The maximum UV index of 12 during December translates into these guidelines:
Put into effect every precaution of importance, unprotected skin and eyes may get burns swiftly. Limit direct sun exposure and seek shade between 10 a.m. and 4 p.m., the time of the most intense UV radiation, noting that shade structures may not provide total sun protection. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck. Regularly apply and reapply a broad-spectrum sunscreen with a minimum SPF 30 every two hours, or straight after swimming or an outdoor activity.