September weather forecast
Belém, Brazil

The month of September in Belém continues with desirable dry and warm weather, despite a slight increase in rainfall from August, which measures up to 145mm (5.71"). The city's vibrant landscapes, reinvigorated after the rains of previous months, make for a stunning visual paradise. Transitioning from the dry to the wet season, September's weather caters to a wide range of activities that cater to various interests. The month is also synonymous with the city's largest religious celebration, the Círio de Nazaré, which distinctly stands out and enhances the city's cultural charm. Despite being a month of transition in terms of rainfall, temperatures and humidity levels remain persistently high.

Temperature

Belém notes a minor change to an average high temperature of a still tropical 32.1°C (89.8°F) in September, remaining consistent with August. Belém, during September, witnesses an average low-temperature of 21.7°C (71.1°F).

Heat index

September's average heat index is estimated at a life-threatening hot 47°C (116.6°F). Remain alert: Heat exhaustion and heat cramps are predicted. Extended effort can lead to heatstroke.
Heat index specifics point out values are for conditions of shade and a slight breeze. Direct sunlight exposure may cause a 15 Fahrenheit (8 Celsius) degrees rise in the heat index.
Note: The heat index, also known as 'felt air temperature' or 'real feel', is a measure of how hot it feels when the actual air humidity is factored in. A person's impression of weather can be shaped by many aspects, among them metabolic variations, pregnancy, and levels of physical activity. The sun, when shining directly, can have a significant impact on the perceived temperature, increasing the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for children. Kids frequently fail to realize the necessity for resting and hydrating. Thirst is an advanced indication of dehydration - hence, maintaining hydration, especially during extended physical activities, becomes essential.
By perspiring, the human body can shed its excessive warmth since evaporated sweat cools it off. With a high level of moisture in the air, the evaporation process becomes less efficient, preventing the body from cooling down efficiently and resulting in a sensation of overheating. Elevated heat gain compared to the body's release capability poses risks of dehydration and potential overheating.

Humidity

In September, the average relative humidity is 84%.

Rainfall

In Belém, during September, the rain falls for 15 days and regularly aggregates up to 145mm (5.71") of precipitation. Throughout the year, there are 221 rainfall days, and 2922mm (115.04") of precipitation is accumulated.

Sea temperature

The months with the coldest seawater are September, October and December, with an average sea temperature of 28.2°C (82.8°F).
Note: For swimming, diving, or other water activities, the temperature range of 25°C (77°F) to 29°C (84.2°F) is perceived as exceptionally enjoyable and comfortable even for prolonged periods.

Daylight

The average length of the day in September is 12h and 6min.
On the first day of September in Belém, sunrise is at 06:11 and sunset at 18:16. On the last day of the month, sunrise is at 06:00 and sunset at 18:07 -03.

Sunshine

The average sunshine in September is 7.7h.

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 estimate of 11, and higher, represents an extreme health hazard from unsafe exposure to UV radiation for the ordinary person.
Note: The maximum daily UV index of 12 in September converts into the following recommendations:
Carry out all vital precautions. Protection from sun exposure is a must. Try to minimize direct Sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation. Also note that objects like parasols or canopies might not provide complete sun protection. Experience reduced UV exposure by about half when donning a wide-brim hat. Even on overcast days, ensure the application and frequent reapplication of sunscreen with at least an SPF 30, especially post swim or outdoor exercise. Caution! Sand and water surfaces escalate the UV intensity from the Sun.