September weather forecast
Grand-Santi, French Guiana

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Weather in September

The weather conditions in Grand-Santi during September record significant changes with the reduction in humidity levels and the steady decrease of rainfall. The lowering pressure values, at 1011.5mb, suggest a smooth climatic transition into the fall season. However, the UV Index remains at 7, indicating a potential risk to skin and eyes from UV rays. Although the weather is slightly cloud-covered, September remains special with the lowest rainfall of the year, marked at 18mm (0.71"), pointing towards drier conditions.

Temperature

The arrival of September in Grand-Santi brings an average high-temperature of a still tropical 34.3°C (93.7°F), closely following the temperature pattern of August. A pronounced dip becomes evident during the nights in September as Grand-Santi logs a consistent average temperature of 21.1°C (70°F).

Heat index

The heat index value for September is calculated to be a burning hot 51°C (123.8°F). Be cautious: Heat exhaustion along with heat cramps are predicted. Heatstroke is a possible consequence of continuous physical effort.
Given the heat index, its values are aligned with shaded sites and gentle winds. Exposing to direct sunshine may enhance heat index values by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'feels like', offers an insight into how hot it feels when we factor in moisture content. A person's impression of weather can be shaped by many aspects, among them metabolic variations, pregnancy, and levels of physical activity. When directly under the sun, the weather's impact can intensify, possibly boosting the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially vital to children. Juveniles are regularly less conscious of the need to recuperate and rehydrate. Thirst is a tardy symptom of dehydration - hydration, especially during lengthy physical activities, should be maintained.
The human body normally cools itself by perspiration, as evaporated sweat carries heat away from the body. 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

The average relative humidity in September is 75%.

Rainfall

September is the month with the least rainfall in Grand-Santi. Rain falls for 10.3 days and accumulates 18mm (0.71") of precipitation.

Daylight

In September, the average length of the day in Grand-Santi is 12h and 8min.
On the first day of September in Grand-Santi, sunrise is at 06:31 and sunset at 18:43. On the last day of the month, sunrise is at 06:24 and sunset at 18:29 -03.

Sunshine

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

UV index

The months with the highest UV index are July through November, with an average maximum UV index of 7. A UV Index of 6 to 7 symbolizes a high health risk from unprotected exposure to Sun's UV rays for average individuals.
Note: A typical high UV index of 7 in September suggests the following recommendations:
Ward off overexposure. Defence against solar harm is crucial. 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. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses.

Frequently asked questions

How hot does it get in Grand-Santi in September?

The high-temperature, in September, in Grand-Santi, records 34.3°C (93.7°F), while the low-temperature is 21.1°C (70°F). The average heat index (a.k.a. 'real feel', 'felt air temperature'), which combines relative humidity and air temperature, in September is calculated to be 51°C (123.8°F).

What is the average humidity in September in Grand-Santi?

The average relative humidity in September in Grand-Santi, French Guiana, is 75%.

What is the driest month in Grand-Santi?

The month with the least rainfall is September, when the rain falls for 10.3 days and typically collects 18mm (0.71") of precipitation.

How much does it rain in Grand-Santi in September?

In Grand-Santi, in September, during 10.3 rainfall days, 18mm (0.71") of precipitation is typically accumulated.

How many hours of daylight does Grand-Santi have in September?

The average day length in September in Grand-Santi is 12h and 8min.

What time are sunrise and sunset in September in Grand-Santi?

On the first day of September, sunrise is at 06:31 and sunset at 18:43. On the last day of the month, sunrise is at 06:24 and sunset at 18:29 -03.

What month has the most sunshine in Grand-Santi?

The month with the most sunshine in Grand-Santi, French Guiana, is September, with an average of 9.1h of sunshine.

How many hours of sunshine does Grand-Santi have in September?

In September, the average sunshine duration in Grand-Santi, French Guiana, is 9.1h.

When is the highest UV index in Grand-Santi?

July through November, with an average maximum UV index of 7, are months with the highest UV index in Grand-Santi.

How high is the UV index in September in Grand-Santi?

In Grand-Santi, French Guiana, the average daily maximum UV index in September is 7. A UV Index value of 6 to 7 symbolizes a high health risk from exposure to Sun's UV rays.

Average temperature in September
Grand-Santi, French Guiana

Average temperature in September - Grand-Santi, French Guiana
  • Average high temperature in September: 34.3°C

The warmest month (with the highest average high temperature) is October (34.8°C).
The month with the lowest average high temperature is February (29.5°C).

  • Average low temperature in September: 21.1°C

The month with the highest average low temperature is May (22°C).
The coldest month (with the lowest average low temperature) is January (20.7°C).

Average pressure in September
Grand-Santi, French Guiana

Average pressure in September - Grand-Santi, French Guiana
  • Average pressure in September: 1011.5mbar

The months with the highest atmospheric pressure are June and July (1012.9mbar).
The month with the lowest atmospheric pressure is November (1009.4mbar).

Average wind speed in September
Grand-Santi, French Guiana

Average wind speed in September - Grand-Santi, French Guiana
  • Average wind speed in September: 5.2km/h

The windiest month (with the highest average wind speed) is March (5.5km/h).
The calmest month (with the lowest average wind speed) is July (4.4km/h).

Average humidity in September
Grand-Santi, French Guiana

Average humidity in September - Grand-Santi, French Guiana
  • Average humidity in September: 75%

The month with the highest relative humidity is May (90%).
The month with the lowest relative humidity is October (73%).

Average rainfall in September
Grand-Santi, French Guiana

Average rainfall in September - Grand-Santi, French Guiana
  • Average rainfall in September: 18mm

The wettest month (with the highest rainfall) is May (171mm).
The driest month (with the least rainfall) is September (18mm).

Average rainfall days in September
Grand-Santi, French Guiana

Average rainfall days in September - Grand-Santi, French Guiana
  • Average rainfall days in September: 10.3 days

The month with the highest number of rainy days is December (28.1 days).
The month with the least rainy days is September (10.3 days).

Average daylight in September /
Average sunshine in September
Grand-Santi, French Guiana

Average daylight in September / Average sunshine in September - Grand-Santi, French Guiana
  • Average daylight in September: 12h and 1min

The month with the longest days is June (Average daylight: 12h and 24min).
The month with the shortest days is December (Average daylight: 11h and 54min).

  • Average sunshine in September: 9h and 1min

The month with the most sunshine is September (Average sunshine: 9h and 6min).
The month with the least sunshine is February (Average sunshine: 4h and 30min).

Average sunshine days in September
Grand-Santi, French Guiana

Average sunshine days in September - Grand-Santi, French Guiana
  • Average sunshine days in September: 17.5 days

The month with the most sunshine days is October (18.8 days).
The month with the least sunshine days is February (1.4 days).

Average UV index in September
Grand-Santi, French Guiana

Average UV index in September - Grand-Santi, French Guiana
  • Average UV index in September: 7

The months with the highest UV index are July, August, September, October and November (UV index 7).
The month with the lowest UV index is December (UV index 5).

Average cloud cover in September
Grand-Santi, French Guiana

Average cloud cover in September - Grand-Santi, French Guiana
  • Average cloud cover in September: 46

The month with the most cloud cover is February (Cloud cover 78).
The month with the least cloud cover is October (Cloud cover 45).

Average visibility in September
Grand-Santi, French Guiana

Average visibility in September - Grand-Santi, French Guiana
  • Average visibility in September: 7km

The months with the highest visibility are August, September, October and November (7km).
The month with the lowest visibility is May (5km).

Grand-Santi, French Guiana

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