Cayenne Monthly Rainfall & Precipitation
This page shows both the average monthly rainfall and the number of rainy days in Cayenne, French Guiana. These averages rely on historical data collected over 30 years, from 1990 to 2020. Let's explore the details to provide you with a complete overview.
Cayenne has a relatively rainy climate with high precipitation levels, averaging 2663 mm (105 in) of rainfall annually. Despite the high annual total, it does experience a distinct rainy season during certain months. Examine our detailed charts below to understand these seasonal patterns.
Monthly Precipitation Levels
The average number of days each month with precipitation (> 0.2 mm (0.01 in))
The climate in Cayenne shows significant variation throughout the year. Expect 403 mm (16 in) of precipitation during the wettest month May, distributed over 26 rainy days.
In contrast, September offers drier and sunnier days, with around 65 mm (2.6 in) of rainfall over 5 rainy days.
May, the wettest month, has a maximum daytime temperature of 30°C (86°F). The city receives 122 hours of sunshine in this period. During the driest month September you can expect a temperature of 32°C (90°F). For more detailed insights into the city's temperatures, visit our Cayenne Temperature page.
Daily Historical Precipitation
49-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in July
Explore Cayenne's Historical Precipitation: 1976-2026
Browse day-by-day precipitation records for Cayenne spanning 51 years. Select any month and year to see actual rainfall and snowfall recorded on each day.
Annual Rainfall in French Guiana: City Comparison
The map below shows the annual precipitation across French Guiana. You can also select the different months in case you are interested in a specific month.
heavy rainfall
high
moderate
low
almost none
Cayenne vs World: Rainfall Compared
Cayenne's average annual precipitation is 2663 mm (105 in). Let's compare this to some popular worldwide tourist destinations:
Boston, USA, experiences 1238 mm (49 in) of annual precipitation, including significant snowfall during the winter.
Beijing, China, receives 560 mm (22 in) of annual precipitation, concentrated in the summer months.
Adelaide, Australia, enjoys 511 mm (20 in) of annual precipitation, with dry summers and wet winters.
Bangkok, Thailand, experiences a tropical monsoon climate with 1668 mm (66 in) of annual rainfall, with the heaviest precipitation occurring during September and October.
Precipitation amounts are measured using specific gauges installed at weather stations, collecting both rain and snow and any other type of precipitation. Rainfall is measured directly in millimeters, while that from snow and ice is obtained by melting it. Automated systems often incorporate heaters to make this easier.
Information from these stations is transmitted via Wi-Fi, satellite, GPS, or telephone connections to central monitoring networks. This information is immediately updated and integrated into weather models and forecasts.
Tropical Rainforests: In tropical regions, rainfall is generally abundant year-round. Areas near the equator, like the Amazon rainforest, can receive up to 3000 mm (118 in) of rain annually.
Desert Regions: Deserts such as the Sahara and Arabian deserts typically see less than 250 mm (9.8 in) of rainfall annually. Rainfall tends to be infrequent, but when it does occur, it is often intense.
Temperate Zones: In temperate regions, precipitation tends to be more evenly distributed, though areas closer to the ocean may see more rain in the winter months, and areas further inland experience drier summers.
Polar Regions: Precipitation in polar regions, like Antarctica, is extremely low, often falling as snow. Average annual precipitation in Antarctica is less than 200 mm (7.9 in), with some areas receiving as little as 50 mm (2 in) annually.
- The U.S. has a significant number of thunderstorms every year, with over 14.6 million taking place across the world annually.
- Approximately 70% of lightning bolts strike land rather than oceans.
- A storm named John was the longest-lasting Pacific tropical storm, continuing for 31 days. As it crossed the dateline twice, it changed status from a hurricane to a typhoon and back to a hurricane.
For more detailed information about Cayenne's weather, including sunshine hours, humidity levels, and temperature data, visit our Cayenne Climate page.
