December weather forecast
São Mateus, Brazil

The first month of the summer, December, is still a warm month in São Mateus, Brazil, with an average temperature ranging between max 28.9°C (84°F) and min 22.8°C (73°F).

Temperature

In December, São Mateus's weather conditions record an average high-temperature of a still moderately hot 28.9°C (84°F), demonstrating little divergence from the preceding month. Nightly temperatures in São Mateus drop to an average low of 22.8°C (73°F) in December.

Heat index

The heat index value for December is appraised at a torrid 35°C (95°F). Take additional safety steps, risk of heat exhaustion and heat cramps is notable. Prolonged activity may cause heatstroke.
Keep in mind the heat index values are meant for areas in shade and with light wind. Exposure to the sun directly might heighten the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'felt air temperature', gives an indication of how one might feel in terms of heat after considering humidity. The effect is personal, with varied weather perceptions among individuals due to differences in body mass, stature, and physical activity. It is essential to be conscious of the fact that direct sunlight can intensify the felt heat, leading to an elevation in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are primarily vital for children. Kids are usually more vulnerable than adults, given their lesser sweating ability. Along with their larger skin surface relative to their small stature and the excess heat due to their activity, their risk is amplified.
The human body normally cools itself by perspiration, as evaporated sweat carries heat away from the body. An increase in relative humidity disrupts body cooling by slowing the evaporation rate, thereby reducing the rate at which the body cools and amplifying the sense of heat. Heat absorption that surpasses the body's shedding capability can lead to overheating and varying levels of dehydration.

Humidity

March, April, June, November and December, with an average relative humidity of 82%, are the most humid months.

Rainfall

The month with the most rainfall is December, when the rain falls for 20 days and typically aggregates up to 143mm (5.63") of precipitation.

Daylight

December has the longest days of the year in São Mateus, Brazil, with an average of 13h and 12min of daylight.
On the first day of the month, sunrise is at 04:53 and sunset at 18:03. On the last day of December, in São Mateus, sunrise is at 05:05 and sunset at 18:19 -03.

Sunshine

The average sunshine in December in São Mateus is 8.5h.

UV index

The months with the highest UV index are January through March and December, with an average maximum UV index of 7. A UV Index value of 6 to 7 symbolizes a high health risk from unsafe exposure to UV radiation for the average person.
Note: In December, the maximum UV index of 7 suggests this advice:
Implement precautions and maintain sun safety methods. Avoidance of sunburn is demanded. The hours from 10 a.m. to 4 p.m. have the most intense UV radiation. As much as possible, limit direct sun exposure during this period. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key.