September weather forecast
São João de Pirabas, Brazil

The first month of the spring, September, is still a hot month in São João de Pirabas, Brazil, with an average temperature ranging between min 22.4°C (72.3°F) and max 32.3°C (90.1°F).

Temperature

With the start of September, São João de Pirabas measures an average high-temperature of a still tropical 32.3°C (90.1°F), not significantly differing from August's 32°C (89.6°F). São João de Pirabas records an average nighttime low-temperature of 22.4°C (72.3°F) throughout September.

Heat index

The heat index in September is estimated at a blazing hot 45°C (113°F). Note: Heat exhaustion and heat cramps are probable. Heatstroke can follow with prolonged activity.
Take note of the fact that heat index values are based on shaded circumstances with light airflows. Exposure to direct sunlight may make the heat index values climb by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'feels like', offers an insight into how hot it feels when we factor in moisture content. This effect is personal, influenced by the individual's physical activity and heat sensitivity, shaped by factors including wind, attire, and metabolic variations. Direct sun rays can make one feel hotter, potentially raising the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly meaningful for babies and toddlers. Youngsters frequently overlook the need for breaks and fluid intake. Thirst is an advanced sign of dehydration - thereby highlighting the importance of keeping hydrated, particularly during long physical activities.
As a reaction to high temperatures, the human body begins to perspire, using the evaporation of sweat to lower its temperature. When relative humidity is on the rise, it curtails evaporation, thereby reducing the heat elimination from the body and causing the feeling of being excessively hot. The body faces dehydration threats when its cooling efforts are outpaced by excessive heat gain.

Humidity

In São João de Pirabas, the average relative humidity in September is 79%.

Rainfall

In São João de Pirabas, in September, during 20.8 rainfall days, 34mm (1.34") of precipitation is typically accumulated. In São João de Pirabas, during the entire year, the rain falls for 307.3 days and collects up to 1390mm (54.72") of precipitation.

Sea temperature

September and October, with an average sea temperature of 28.3°C (82.9°F), are months with the coldest seawater.
Note: Water temperature between 25°C (77°F) and 29°C (84.2°F) is regarded as very warm and enjoyable by all. With these temperatures, water activities are pleasurable, without feeling uncomfortable for prolonged periods.

Daylight

In São João de Pirabas, the average length of the day in September is 12h and 7min.
On the first day of September, sunrise is at 06:05 and sunset at 18:11. On the last day of the month, sunrise is at 05:54 and sunset at 18:02 -03.

Sunshine

With an average of 8.5h of sunshine, September has the most sunshine of the year.

UV index

The months with the highest UV index in São João de Pirabas are July, September and October, with an average maximum UV index of 7. A UV Index reading of 6 to 7 represents a high threat to health from unprotected exposure to Sun's UV rays for average individuals.
Note: The daily high UV index of 7 in September translates into this advice:
Take precautions and utilize sun safety practices. Protection against skin and eye damage is required. The Sun's UV radiation is at its strongest between the hours of 10 a.m. and 4 p.m. Minimize direct exposure to the sun during this period. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Alert! Sand and water increase UV exposure due to their reflective properties.