January weather forecast
Castanhal, Brazil

January, like December, is another hot summer month in Castanhal, Brazil, with an average temperature ranging between max 30.6°C (87.1°F) and min 22.5°C (72.5°F).

Temperature

The arrival of January sees a recorded average high-temperature of a still hot 30.6°C (87.1°F), showing little divergence from the previous month's conditions. Castanhal reports an average low-temperature of 22.5°C (72.5°F) during the nights of January.

Heat index

For most parts of January, the heat index is calculated to be a blistering 42°C (107.6°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. The heat index may scale up by 15 Fahrenheit (8 Celsius) degrees with direct sun exposure.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', is found by incorporating humidity levels into the air temperature measurement. An individual's perception of weather can be influenced by a variety of factors including metabolic differences, being pregnant, and their degree of physical exertion. Recognize that direct exposure to the sun can escalate the heat effect, potentially adding 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are of high significance for children. Children often overlook the necessity for resting and fluid replenishment. Thirst is a late sign of dehydration - thus, it is critical to stay hydrated, especially during extended periods of physical activities.
In high temperatures, perspiration kicks in, allowing the human body to cool down through the evaporation of sweat. When relative humidity increases, the body's capacity to evaporate heat decreases, leading to a heightened sense of warmth. As the body accumulates more heat than it can release, body temperature goes up, increasing the risk of heat-related health issues.

Humidity

The average relative humidity in January is 87%.

Rainfall

In Castanhal, in January, it is raining for 30.3 days, with typically 164mm (6.46") of accumulated precipitation. In Castanhal, during the entire year, the rain falls for 332.9 days and collects up to 1589mm (62.56") of precipitation.

Daylight

The average length of the day in January is 12h and 11min.
On the first day of January in Castanhal, sunrise is at 06:09 and sunset at 18:20. On the last day of the month, sunrise is at 06:19 and sunset at 18:30 -03.

Sunshine

In January, the average sunshine is 6.2h.

UV index

January through April, June, August and December, with an average maximum UV index of 6, are months with the lowest UV index in Castanhal, Brazil. A UV Index of 6 to 7 symbolizes a high health vulnerability from exposure to the Sun's UV radiation for the ordinary person.
Note: A daily high UV index of 6 in January leads to these guidelines:
Prevent overexposure. Protection from the sun's harmful effects is needed. The Sun's UV radiation is most potent between the hours of 10 a.m. and 4 p.m. Try to avoid direct sunlight during this time. 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.