Grand Bourg's climate is characterized by mild winters and hot summers. The coldest months are June, July, and August, with temperatures ranging from -3°C to 28°C, averaging around 11-12°C. Spring and autumn are pleasant, with temperatures gradually rising and falling between 20-26°C. Summer brings scorching heat, with temperatures often reaching over 40°C in December and January. The warmest months, December, January, and November, see average highs around 24-25°C, while the rest of the year remains relatively cool to mild.