Sinnamary is warm all year: afternoons reach 29 to 32 degrees in every month
Twelve months of showers and storms leave about 2,810 mm. Set against mainland French towns, none of its figures stands out. Only 9°C separates winter nights from summer afternoons.
Figures from Météo-France’s Kourou Csg station, 30 km south-east: at that distance, read them as the area’s climate rather than the town’s.
A year in Sinnamary at a glance
Each month’s typical high and low in °C, at the Kourou Csg station.
What a year in Sinnamary feels like
Typical highs and lows in the rainier and the drier half of the year, and by month, from Météo-France’s 1991–2020 normals at Kourou Csg.
About 2,810 mm of rain a year
May is the wettest month and September the driest. About 80 days a year bring 10 mm or more. 11th wettest of 15 towns of 2,500+ in French Guiana.
Rain by month
Millimeters
Sunshine by month
Hours of sunshine at Cayenne-Matoury
The Météo-France station at Kourou Csg
Kourou Csg is 30 km south-east of Sinnamary. Every figure on this page is the station’s, not a measurement in Sinnamary itself.
| Station (Météo-France number) | Kourou Csg (97304003) |
| Distance from the town | 30 km south-east |
| Station altitude | 17 m |
| Town altitude (its center) | 6 m |
| Period | 1991–2020 |
| Nearest station of any kind | 4.7 km |
| Sunshine measured at | Cayenne-Matoury, 90 km away |
TownRatings matches each commune to one station with at least 24 years of temperature and rain records: the nearest, counting every 100 m of height difference as 10 km, never across the sea.
How Sinnamary compares
Against the 15 towns of 2,500+ in French Guiana (the dots). Mainland France’s towns aren’t a fair comparison for a tropical climate.
Sinnamary weather by month
Average daily high and low, mean temperature and rain, 1991–2020, at the Kourou Csg station; sunshine at Cayenne-Matoury.
| Month | High | Low | Mean | Rain | Sun (hours) |
|---|---|---|---|---|---|
| January | 29.2°C | 24.0°C | 26.6°C | 320 mm | 102 |
| February | 29.3°C | 24.1°C | 26.7°C | 252 mm | 90 |
| March | 29.6°C | 24.5°C | 27.0°C | 246 mm | 117 |
| April | 29.7°C | 24.5°C | 27.1°C | 406 mm | 121 |
| May | 29.7°C | 24.2°C | 26.9°C | 489 mm | 121 |
| June | 29.9°C | 23.4°C | 26.6°C | 382 mm | 153 |
| July | 30.6°C | 22.9°C | 26.7°C | 165 mm | 200 |
| August | 31.2°C | 22.9°C | 27.1°C | 82 mm | 231 |
| September | 31.9°C | 22.9°C | 27.4°C | 28 mm | 251 |
| October | 32.2°C | 22.9°C | 27.6°C | 42 mm | 257 |
| November | 31.4°C | 23.3°C | 27.4°C | 125 mm | 208 |
| December | 30.0°C | 23.8°C | 26.9°C | 274 mm | 150 |
| Year | 30.4°C | 23.6°C | 27.0°C | 2,810 mm | 2,003 |
Where Sinnamary’s numbers come from
Averages over 30 years, not a forecast.
- Temperature, rain and day counts: Météo-France’s fiche climatologique for Kourou Csg, 30 km away: statistics for 1991–2020.
- Which station: among stations with at least 24 of the 30 years of temperature and rain, the nearest to the commune’s population-weighted center, counting each 100 m of height difference as 10 km; mainland towns use mainland stations and each overseas département its own.
- Altitudes: the town’s from IGN’s RGE ALTI® at its population-weighted center; the station’s from Météo-France.
- Sunshine: the nearest station with at least 10 years of sunshine records, Cayenne-Matoury, 90 km away.
- Comparisons: the towns of 2,500+ in French Guiana, read the same way.
Météo-France fiches climatologiques · IGN RGE ALTI®. Licence Ouverte 2.0.
Questions about Sinnamary’s climate
How warm does Sinnamary get in summer?
October is the warmest month, with average highs of 32.2°C. Météo-France publishes no count of hot days for this station.
Does Sinnamary ever get cool?
Not much: the coolest nights, in July, average 22.9°C.
How much rain does Sinnamary get?
About 2,810 mm a year. May is the wettest month (489 mm) and September the driest (28 mm).
How sunny is it?
The nearest Météo-France station that records sunshine, Cayenne-Matoury (90 km away), averages 2,003 hours of sunshine a year.
Are these figures for Sinnamary itself?
No: they are the normals of the Météo-France station matched to Sinnamary, Kourou Csg, 30 km away. France publishes its climate normals by station, not by commune; a valley, a hill or the sea can make a difference over a few kilometers.
Where do these figures come from?
Météo-France’s fiches climatologiques: 30-year averages (1991–2020) for each of its long-running stations, published as open data since 2024. They are normals, not a forecast.
Source: Météo-France, fiches climatologiques, 1991–2020 statistics (station KOUROU CSG, edited 15/10/2026); altitude: IGN, RGE ALTI®. Licence Ouverte 2.0. Today’s forecast for Sinnamary →
Contains public sector information under the Licence Ouverte / Open Licence 2.0 (Etalab): INSEE, DGFiP, the Interior Ministry’s statistics service (SSMSI), the Ministry of Education (DEPP), the Health Ministry’s statistics service (DREES) and the Housing Ministry (Carte des loyers). Commune boundaries: IGN Admin Express.