September weather forecast
La Grève, French Guiana

The first month of the autumn, September, is also a hot month in La Grève, French Guiana, with an average temperature fluctuating between 34.1°C (93.4°F) and 20.5°C (68.9°F).

Temperature

La Grève's average high-temperature marks a still hot 34.1°C (93.4°F) with the advent of September, closely mirroring that of the preceding month. September nights in La Grève experience a distinct temperature drop from the daily highs, with an average low-temperature of 20.5°C (68.9°F).

Heat index

In September, the heat index is appraised at a burning hot 49°C (120.2°F). Be wary: Heat exhaustion and heat cramps are highly anticipated. With continued activity, heatstroke is very likely.
Consider that heat index readings are for situations in the shade and light wind. Direct sunlight might lead to a heat index increase by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'feels like', is a measure that combines air temperature and relative humidity into a single value that indicates how hot the weather feels. An individual's temperature experience can be influenced by extra factors, including metabolic differences, activity levels, and clothing. With the sun shining directly, it's crucial to understand that it can increase the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular significance for children. 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.
The evaporation of sweat is a natural cooling mechanism of the human body, facilitated by perspiration. In the presence of high relative humidity, the evaporation rate diminishes, resulting in the body retaining more warmth compared to dry conditions. Overheating can ensue when the body accumulates more heat than it can release, and dehydration severity may vary.

Humidity

In La Grève, the average relative humidity in September is 74%.

Rainfall

In September, in La Grève, the rain falls for 14.3 days. Throughout September, 36mm (1.42") of precipitation is accumulated. Throughout the year, there are 265.5 rainfall days, and 1078mm (42.44") of precipitation is accumulated.

Daylight

The average length of the day in September in La Grève is 12h and 8min.
On the first day of the month, sunrise is at 06:28 and sunset at 18:40. On the last day of September, in La Grève, sunrise is at 06:21 and sunset at 18:27 -03.

Sunshine

The months with the most sunshine are September and October, with an average of 8.8h of sunshine.

UV index

The months with the highest UV index in La Grève are August through November, with an average maximum UV index of 7. A UV Index estimate of 6 to 7 represents a high health hazard from exposure to the Sun's UV rays for ordinary individuals.
Note: In September, the maximum UV index of 7 suggests these recommendations:
Dodge overexposure. Fair-skinned people can get singed in less than 20 minutes. Stay in the shade and limit sun exposure from 10 a.m. to 4 p.m., when UV radiation is most potent. Keep in mind that shade structures like parasols or canopies do not offer full protection. Safeguard your eyes, ears, and face from sun rays with the aid of a wide-brim hat.