December weather forecast
Castanhal, Brazil

December, the first month of the summer in Castanhal, is also a hot month, with temperature in the range of an average low of 23°C (73.4°F) and an average high of 32°C (89.6°F).

Temperature

Upon the beginning of December, Castanhal's high-temperatures register at a still tropical 32°C (89.6°F), closely mirroring the preceding month. Throughout December nights, Castanhal registers an average low-temperature of 23°C (73.4°F).

Heat index

For December, the heat index is calculated to be a blisteringly hot 44°C (111.2°F). Stay on guard: Heat exhaustion and heat cramps are predicted. Ongoing effort can cause heatstroke.
Bear in mind that the heat index values are determined for shaded areas and light breezes. Facing direct sunlight may hike up the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', integrates the air's temperature and its humidity to showcase the felt temperature by people. This impact is subjective, influenced by the person's physical activity and individual heat perception, affected by factors including wind, attire, and metabolic differences. Direct sun rays have a notable impact on perceived temperature, which can raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for babies and toddlers. Children commonly overlook the importance of rest and fluid replenishment. Thirst, being a delayed sign of dehydration, emphasizes the need to keep hydration up, especially during lengthy physical activities.
The natural method the human body uses to remove excess heat is by perspiring and letting sweat evaporate. An increase in relative humidity hinders the body's normal cooling function by reducing evaporation, thereby decreasing the rate of body cooling and enhancing the sense of warmth. Increasing body temperatures can be a precursor to dehydration if the body can't shed the extra heat.

Humidity

The average relative humidity in December in Castanhal is 80%.

Rainfall

In Castanhal, in December, it is raining for 28.2 days, with typically 142mm (5.59") of accumulated precipitation. Throughout the year, there are 332.9 rainfall days, and 1589mm (62.56") of precipitation is accumulated.

Daylight

With an average of 12h and 12min of daylight, December has the longest days of the year in Castanhal.
On the first day of the month, sunrise is at 05:55 and sunset at 18:06. On the last day of December, sunrise is at 06:09 and sunset at 18:20 -03.

Sunshine

The average sunshine in December in Castanhal, Brazil, is 7h.

UV index

January through April, June, August and December, with an average maximum UV index of 6, are months with the lowest UV index. A UV Index estimate of 6 to 7 represents a high health risk from exposure to the Sun's UV rays for ordinary individuals.
Note: The maximum daily UV index of 6 during December translates into the following directions:
Dodge overexposure. Fair-skinned people can get singed in less than 20 minutes. Stay in the shade and avoid direct Sun exposure from 10 a.m. to 4 p.m., a time when UV radiation is at its strongest, and remember that parasols or canopies do not offer full protection. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays.