The climate is tropical and very warm. Coastal areas are hot and very humid, interspaced with rains and seasonal cyclones (January to April). The upland areas are cooler, particularly at night, and have higher rainfall. The rainy season is from November to April.

Lightweight cottons and linens with waterproofing during the rainy season. Warmer garments and rainwear are needed for the mountains.

The Comoro archipelago is situated in the Indian Ocean north of Madagascar and consists of four main islands of volcanic origin, surrounded by coral reefs: Ngazidja (formerly Grande Comore), Nzwani (formerly Anjouan), Mwali (formerly Mohéli) and Mahoré (Mayotte). The latter is administered by France but is claimed by the Federal Islamic Republic of the Comoros. Land can only support subsistence agriculture but the surrounding seas are rich in marine life.