September weather forecastGrigel, French Guiana
September
Weather in September
The first month of the autumn, September, is still a hot month in Grigel, French Guiana, with an average temperature fluctuating between 20.5°C (68.9°F) and 34.1°C (93.4°F).Temperature
September's average high-temperature is a still hot 34.1°C (93.4°F), maintaining a close comparison with August's 32.8°C (91°F). September, marked by an average low-temperature of 20.5°C (68.9°F), indicates a large temperature drop from the daytime peak.Heat index
The heat index in September is computed to be a life-threatening hot 49°C (120.2°F). Take note: Heat exhaustion and heat cramps are expected. Heatstroke can occur with prolonged effort.Heat index's context suggests values are appropriate for shady areas and slight breezes. The direct sun can potentially cause the heat index to increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', is an estimation of the warmth sensation when considering humidity levels. A person's impression of weather can be swayed by numerous aspects, among them metabolic variations, pregnancy, and activity levels. Direct exposure to sun rays can potentially augment the heat sensation, elevating the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical to babies and toddlers. Youngsters are usually more at risk than adults, considering they sweat less. Additionally, their high skin surface area compared to their little bodies and their high heat production due to activity increases their risk.
Perspiring is how the human body naturally cools down, as sweat's evaporation takes away excess heat. In the presence of abundant moisture in the atmosphere, the cooling process through evaporation is hindered, causing the body to feel excessively warm. When heat gain surpasses the level the body can shed, body temperature begins to increase, and consequently, overheating and dehydration can occur, with varying severity.
Humidity
In Grigel, French Guiana, the average relative humidity in September is 74%.Rainfall
In Grigel, French Guiana, in September, during 14.3 rainfall days, 36mm (1.42") of precipitation is typically accumulated. In Grigel, French Guiana, during the entire year, the rain falls for 265.5 days and collects up to 1078mm (42.44") of precipitation.Daylight
In Grigel, French Guiana, the average length of the day in September is 12h and 8min.On the first day of September, sunrise is at 06:29 and sunset at 18:39. On the last day of the month, sunrise is at 06:21 and sunset at 18:27 -03.
Sunshine
September and October, with an average of 8.8h of sunshine, are months with the most sunshine in Grigel.UV index
The months with the highest UV index in Grigel 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 radiation for the average person.Note: During September, 7 as the daily maximum UV index converts into the following advice:
Persist in precautions and follow sun safety policies. Keeping sunburn at bay is imperative. Minimize exposure to direct sunlight and seek shade from 10 a.m. to 4 p.m., when UV radiation is most intense, but remember that shade structures may not offer complete protection. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Grigel, French Guiana
- Average high temperature in September: 34.1°C
The warmest month (with the highest average high temperature) is October (34.9°C).
The month with the lowest average high temperature is February (29.3°C).
- Average low temperature in September: 20.5°C
The month with the highest average low temperature is May (21.9°C).
The coldest months (with the lowest average low temperature) are August and September (20.5°C).
Average pressure in September
Grigel, French Guiana
- Average pressure in September: 1011.6mbar
The months with the highest atmospheric pressure are June and July (1013mbar).
The month with the lowest atmospheric pressure is November (1009.4mbar).
Average wind speed in September
Grigel, French Guiana
- Average wind speed in September: 4.9km/h
The windiest months (with the highest average wind speed) are February, March and November (5.3km/h).
The calmest month (with the lowest average wind speed) is July (4.2km/h).
Average humidity in September
Grigel, French Guiana
- Average humidity in September: 74%
The month with the highest relative humidity is May (90%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Grigel, French Guiana
- Average rainfall in September: 36mm
The wettest month (with the highest rainfall) is May (192mm).
The driest month (with the least rainfall) is October (21mm).
Average rainfall days in September
Grigel, French Guiana
- Average rainfall days in September: 14.3 days
The months with the highest number of rainy days are January and March (26.8 days).
The month with the least rainy days is October (10.4 days).
Average daylight in September /
Average sunshine in September
Grigel, French Guiana
- Average daylight in September: 12h and 6min
The month with the longest days is June (Average daylight: 12h and 18min).
The month with the shortest days is December (Average daylight: 11h and 54min).
- Average sunshine in September: 8h and 48min
The months with the most sunshine are September and October (Average sunshine: 8h and 48min).
The month with the least sunshine is February (Average sunshine: 4h and 0min).
Average sunshine days in September
Grigel, French Guiana
- Average sunshine days in September: 13.3 days
The month with the most sunshine days is October (17.3 days).
The month with the least sunshine days is February (1.8 days).
Average UV index in September
Grigel, French Guiana
- Average UV index in September: 7
The months with the highest UV index are August, September, October and November (UV index 7).
The months with the lowest UV index are January, March and December (UV index 5).
Average cloud cover in September
Grigel, French Guiana
- Average cloud cover in September: 45
The month with the most cloud cover is February (Cloud cover 81).
The month with the least cloud cover is October (Cloud cover 44).
Average visibility in September
Grigel, French Guiana
- Average visibility in September: 7km
The month with the highest visibility is October (8km).
The month with the lowest visibility is May (5km).





