In terms of precipitation, rainfall in French Guiana ranges from 40.0 - 510.0 mm per month. May is typically the wettest month, when rainfall can reach 510.0 mm. September is typically the driest time to visit French Guiana when rainfall is around 40.0 mm.
If weather is an important factor for your trip to French Guiana, use this chart to help with planning. For those seeking warmer temperatures, September is the ideal time of year to visit, when temperatures reach an average of 27.0 C. Travellers hoping to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 26.0 C).