September weather forecast
John, French Guiana

The first month of the autumn, September, is also a hot month in John, French Guiana, with an average temperature varying between 32.7°C (90.9°F) and 22.5°C (72.5°F).

Temperature

John records an average high-temperature of a still tropical 32.7°C (90.9°F) in September, closely mirroring the climate of the previous month. During September, John experiences a consistent low-temperature average of 22.5°C (72.5°F).

Heat index

For September, the heat index is evaluated at a burning hot 47°C (116.6°F). Eyes open: Heat cramps and heat exhaustion are expected. Prolonged exertion could lead to heatstroke.
Regarding the heat index, one should be aware it's determined by shaded settings and mild winds. Under direct sunshine, the heat index values might be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'felt air temperature', is a fusion of air temperature and moisture levels to demonstrate the sensation of heat. A person's impression of weather can be shaped by many aspects, among them metabolic variations, pregnancy, and levels of physical activity. Awareness of direct sun exposure is crucial as it has the potential to heighten the weather's effects, pushing up the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for babies and toddlers. Kids are usually in more danger than grown-ups as they tend to sweat less. Plus, their bigger skin surface in relation to their small frames and increased heat generation due to their activity level make them more susceptible.
Evaporating sweat, an outcome of perspiration, is key in assisting the human body to moderate its temperature. When the air contains significant moisture, the efficiency of the evaporation process decreases, preventing the body from cooling down effectively and creating a feeling of overheating. Overheating risks increase with rising body temperatures, especially if heat release isn't efficient.

Humidity

In John, the average relative humidity in September is 79%.

Rainfall

In John, in September, during 11.5 rainfall days, 26mm (1.02") of precipitation is typically accumulated. Throughout the year, there are 253 rainfall days, and 878mm (34.57") of precipitation is accumulated.

Daylight

In September, the average length of the day in John is 12h and 8min.
On the first day of September in John, sunrise is at 06:27 and sunset at 18:40. On the last day of the month, sunrise is at 06:21 and sunset at 18:26 -03.

Sunshine

With an average of 9.1h of sunshine, September has the most sunshine of the year.

UV index

July through November, with an average maximum UV index of 7, are months with the highest UV index. A UV Index estimate of 6 to 7 represents a high health vulnerability from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: A maximum high UV index of 7 in September translates into the following recommendations:
Use protective steps and abide by sun safety guidelines. Safeguarding against skin and eye harm is necessary. Remember that the sun's UV radiation is strongest between 10 a.m. and 4 p.m. Make an effort to avoid direct sun exposure during these hours. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized.