French Guiana has a tropical climate and is not hit by tropical cyclones. Temperatures average around 28 ° C and are relatively stable all year round in both the rainy and dry seasons.
There is a comparatively high humidity of more than 80%. The coastal regions benefit from the Atlantic trade winds during the day.
The dry season is between July and December. The other months, with the exception of March, are the rainy season. The wettest month is May.
The best time to travel is in the dry season between July and December. Then the temperatures are a little higher than in the rest of the year, but the probability of rain drops significantly. In the rainy season, the most precipitation falls in May.
Average daytime temperature
| Region | Jan | Feb | March | Apr | May | June | July | Aug | Sep | Oct | Nov | Dec |
| Cayenne- Rochambeau | 28 ° C | 28 ° C | 29 ° C | 29 ° C | 29 ° C | 29 ° C | 30 ° C | 31 ° C | 31 ° C | 31 ° C | 30 ° C | 29 ° C |
Average night temperature
| Region | Jan | Feb | March | Apr | May | June | July | Aug | Sep | Oct | Nov | Dec |
| Cayenne-Rochambeau | 22 ° C | 22 ° C | 23 ° C | 23 ° C | 23 ° C | 22 ° C | 22 ° C | 21 ° C | 21 ° C | 21 ° C | 22 ° C | 22 ° C |
Average water temperature
| Region | Jan | Feb | March | Apr | May | June | July | Aug | Sep | Oct | Nov | Dec |
| Kourou | 27 ° C | 27 ° C | 27 ° C | 28 ° C | 28 ° C | 28 ° C | 28 ° C | 28 ° C | 28 ° C | 28 ° C | 28 ° C | 28 ° C |
Average hours of sunshine / day
| Region | Jan | Feb | March | Apr | May | June | July | Aug | Sep | Oct | Nov | Dec |
| Cayenne-Rochambeau | 4 | 4 | 4 | 5 | 4 | 5 | 6 | 7 | 8 | 8 | 7 | 5 |
Average rainy days / month
| Region | Jan | Feb | March | Apr | May | June | July | Aug | Sep | Oct | Nov | Dec |
| Cayenne-Rochambeau | 24 | 21 | 21 | 23 | 26 | 26 | 20 | 15 | 9 | 10 | 14 | 23 |