The best months to visit French Guiana are October and September. See monthly temperatures, rainfall and rain days (1991–2020 averages) to plan your trip.
Average daytime high and monthly rainfall in French Guiana: January 29°C / 275mm; February 31°C / 234mm; March 31°C / 187mm; April 30°C / 281mm; May 30°C / 430mm; June 30°C / 382mm; July 30°C / 243mm; August 32°C / 126mm; September 34°C / 62mm; October 33°C / 71mm; November 32°C / 163mm; December 28°C / 296mm.