Cayenne
French Guiana
Long-term weather forecast
Long-term weather forecast

September weather forecast and climate
Cayenne, French Guiana

Palm trees in a botanical garden in Cayenne, French Guiana, overlooking green fields under clear skies
Palm trees in a botanical garden in Cayenne, French Guiana, overlooking green fields under clear skies
The first month of the autumn, September, is also a hot month in Cayenne, French Guiana, with average temperature varying between 22.2°C (72°F) and 32.1°C (89.8°F).

Temperature

In Cayenne, the average high-temperature in September is almost the same as in August - a still hot 32.1°C (89.8°F). In September, the average low-temperature is 22.2°C (72°F).

Rainfall

September is the month with the least rainfall. Rain falls for 7.1 days and accumulates 55.7mm (2.2") of precipitation.

Sea temperature

In Cayenne, in September, the average water temperature is 28.5°C (83.3°F).
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 September, the average length of the day in Cayenne is 12.1h.

Sunshine

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

UV index

January through June, August through November, with an average maximum UV index of 12, are months with the highest UV index. A UV Index value of 11, and more, symbolizes an extreme health hazard from unprotected exposure to the Sun's UV rays for the average person.
Note: The daily maximum UV index of 12 interpret into the following advice:
Take all required precautions, as unprotected skin and eyes can burn in minutes. The Sun's UV radiation is most powerful between 10 a.m. and 4 p.m. To the extent possible, limit exposure to the direct sun during these hours. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes. Even on cloudy days, a sunscreen with a minimum 30 sun protection factor should be generously applied and frequently re-applied, including after every swim or outdoor exercise. Beware! The reflection of water and sand dramatically increases exposure to the UV rays.

What is the temperature in September in Cayenne?

In Cayenne, French Guiana, in September, the average high-temperature is 32.1°C (89.8°F), and the average low-temperature is 22.2°C (72°F).

How much does it rain in Cayenne in September?

In Cayenne, during September, the rain falls for 7.1 days and regularly aggregates up to 55.7mm (2.2") of precipitation.

What is the driest month in Cayenne?

The month with the least rainfall is September when the rain falls for 7.1 days and typically collects 55.7mm (2.2") of precipitation.

What is the sea water temperature in September in Cayenne?

In Cayenne, French Guiana, the average seawater temperature in September is 28.5°C (83.3°F). For swimming, diving, and other water activities, temperatures between 25°C (77°F) and 29°C (84.2°F) are perceived as very enjoyable and pleasurable for prolonged periods without feeling uncomfortable.

How many hours of daylight does Cayenne have in September?

In Cayenne, the average length of the day in September is 12.1h.

What month has the most sunshine in Cayenne?

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

How many hours of sunshine does Cayenne have in September?

The average sunshine in September in Cayenne, French Guiana, is 8.5h.

When is the highest UV index in Cayenne?

Months with the highest UV index in Cayenne are January through June, August through November, with an average maximum UV index of 12.

What is the UV index intensity in September in Cayenne?

In September, the average daily maximum UV index is 12. A UV Index estimate of 11, and higher, represents an ultimate hazard to health from unprotected exposure to the UV radiation.
Average temperature in September - Cayenne, French Guiana
  • Average high temperature in September: 32.1°C

The warmest month (with the highest average high temperature) is October (32.2°C).
The month with the lowest average high temperature is January (29.1°C).

  • Average low temperature in September: 22.2°C

The month with the highest average low temperature is April (23.7°C).
The coldest month (with the lowest average low temperature) is September (22.2°C).

Average rainfall in September - Cayenne, French Guiana
  • Average rainfall in September: 55.7mm

The wettest month (with the highest rainfall) is May (579.4mm).
The driest month (with the lowest rainfall) is September (55.7mm).

Average rainfall days in September - Cayenne, French Guiana
  • Average rainfall days in September: 7.1 days

The month with the highest number of rainy days is May (26.4 days).
The month with the lowest number of rainy days is September (7.1 days).

Average sea temperature in September - Cayenne, French Guiana
  • Average sea temperature in September: 28.5°C

The best month for swimming (with the highest average sea temperature) is August (28.7°C).
The coldest month (with the lowest average sea temperature) is February (27.3°C).

Average daylight in September / Average sunshine in September - Cayenne, French Guiana
  • Average daylight in September: 12.1h

Months with the longest days are June and July (Average daylight: 12.4h).
The month with shortest days is December (Average daylight: 11.8h).

  • Average sunshine in September: 8.5h

The month with most sunshine is September (Average sunshine: 8.5h).
The month with least sunshine is January (Average sunshine: 3h).

Average UV index in September - Cayenne, French Guiana
  • Average UV index in September: 12

Months with the highest UV index are January, February, March, April, May, June, August, September, October and November (UV index 12).
Months with the lowest UV index are July and December (UV index 11).