Cayenne, French Guiana · UTC-3 ☆

Cayenne is the capital of French Guiana, an overseas department of France located on South America’s northeastern coast. It runs on America/Cayenne: UTC-3, year-round. French Guiana does not observe daylight saving time.

French Guiana is constitutionally part of France and therefore part of the European Union, making it the EU’s only territory on continental South America. Yet it uses UTC-3 rather than any European timezone. This is practical: France’s Caribbean departments (Martinique, Guadeloupe) use UTC-4, and French Guiana’s South American neighbors use UTC-3. Aligning with the local region makes sense.

The rocket coast

French Guiana is home to the Guiana Space Centre (CSG) at Kourou, from which the European Space Agency’s Ariane rockets launch. Kourou was chosen in the 1960s partly because of its location near the equator (5 degrees north): equatorial launches give rockets a head start from Earth’s rotation, reducing fuel needs for geostationary orbit. The space center operates on a global schedule coordinating with tracking stations, satellite operators, and mission control centers on European time.

Launch timing is dictated by orbital mechanics: launch windows open at specific UTC times regardless of local time in Cayenne. The space center community navigates constant timezone translation between Cayenne’s UTC-3, Paris’s CET, and the UTC timestamps used in launch documentation.

South American borders

French Guiana borders Brazil to the south and east, and Suriname to the west. Brazil’s Amapá state uses UTC-3, the same as Cayenne. Blauwgrond in Suriname uses UTC-3 as well. The regional consistency makes cross-border activity straightforward.

The time conversion from Cayenne to London puts London three hours ahead in winter, four in summer when the UK observes BST.

Sources

• IANA Time Zone Database
• Guiana Space Centre (CSG)
• INSEE French Guiana