French Guiana weather in September 2025

Q: How hot is it in French Guiana in September?

Daytime temperatures usually reach 32°C in Cayenne, French Guiana in September with very high heat and humidity, falling to 23°C at night.

Q: How sunny is it in French Guiana in September?

There are normally 8 hours of bright sunshine each day in Cayenne, French Guiana in September - that's 68% of daylight hours.

Q: How warm is the sea around French Guiana in September?

The average sea temperature around Cayenne, French Guiana in September is 28°C.

Q: Does it rain in French Guiana in September?

There are usually 4 days with some rain in Cayenne, French Guiana in September and the average monthly rainfall is 40mm.

Expect 32°C daytime maximum temperatures in the shade with on average 8 hours of sunshine per day in French Guiana in September based on long-term weather averages. There is usually 4 days with some rainfall and 40 mm of average monthly rainfall in September.

32
32°C max day temperature
8
8 hours of sunshine per day
4
4 days with some rainfall
23
23°C min night temperature
12
12 hours of daylight per day
VH
Very High heat & humidity
40
40 mm of monthly rainfall
11
11+ (Extreme) UV index
28
28°C sea temperature

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The September weather guide for French Guiana, represented by Cayenne, (Cayenne) shows long term weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

Metric (°C / mm) | Imperial (°F / inches)

How hot is it in French Guiana in September?

Daytime temperatures usually reach 32°C in Cayenne, French Guiana in September with very high heat and humidity, falling to 23°C at night.

How sunny is it in French Guiana in September?

There are normally 8 hours of bright sunshine each day in Cayenne, French Guiana in September - that's 68% of daylight hours.

How warm is the sea around French Guiana in September?

The average sea temperature around Cayenne, French Guiana in September is 28°C.

Does it rain in French Guiana in September?

There are usually 4 days with some rain in Cayenne, French Guiana in September and the average monthly rainfall is 40mm.

French Guiana September sunrise & sunset times

Browse the sunrise and sunset times for French Guiana in September 2025. Select a month to view French Guiana sunrise and sunset times for the next 12 months. The French Guiana sunrise and sunset times shown below are for Cayenne.

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