The climate in French Guiana

Climate zone: tropics

High humidity and hot temperatures make the weather in French Guiana pleasant at times but also tropical humid. It is warm or hot yearlong. Due to less rain, the best time for traveling is from August to November. Most precipitation falls from January to June.

Temperature records of the last 73 years

The hottest temperature measured from 1950 to January 2023 was reported by the Saint Laurent du Maroni weather station. In September 2016, the record temperature of 38.0 °C was reported here. The hottest summer from July to September, based on all 4 weather stations in French Guiana , was recorded in 1998 with an average temperature of 27.0 °C. This average temperature will normally be measured every four to six hours, thus also including the nights. Normally, this value is 26.4 degrees Celsius. The average maximum daily temperature at that time was 32.6 °C.

The coldest day in these 73 years was reported by the Cayenne Matoury weather station. Here the temperature dropped to 18.6 °C in January 2020. Cayenne Matoury lies at an altitude of nine meters above sea level. The coldest winter (January to March) was in 1971 with an average temperature of 24.8 °C. In French Guiana, it is usual to have about 1.0 degrees more at 25.8 °C for this three-month period.

The most precipitation fell in May 1984. With 32.9 mm per day, the Cayenne Matoury weather station recorded the highest monthly average of the last 73 years.

Long-term development of temperatures from 1991 - 2022

In contrast to single record values, long-term development cannot simply be brought about by all weather stations in the country. Both the number and the locations are constantly changing. An average value would give a distorted result. If several measuring stations in particularly cold mountain or coastal regions are added in one year, the average would decrease as a result of this alone. If a station fails during the summer or winter months, it does not provide any values and distorts the average again. The subsequent long-term development was therefore reduced to only 1 measuring points in order to have comparable data over as long a period as possible.

In the years 1991 to 2022, there were only these 1 weather stations in the whole country, which reported continuous temperature values (Cayenne Matoury). From these weather reports, we have created a long-term development that shows the monthly average temperatures. The hottest month in this entire period was October 2004 at 27.7 °C. February 2022 was the coldest month with an average temperature of 24.8 °C.

The average annual temperature was about 26.1 °C in the years after 1991 and about 26.3 °C in the last years before 2022. So it has hardly changed at all in the past 32 years. This trend only applies to the selected 1 weather stations in French Guiana. A considerably more comprehensive evaluation of global warming has been provided separately.

Data basis and methodology

The data from the individual measuring stations are based on the archives of the German Weather Service, individual values averaged and supplemented by own elements. In order to determine a representative national average, average values were first calculated for each part of the country, which were then summarized at the national level.