The Comoro Islands or Comoros form an archipelago of volcanic islands situated off the south-east coast of Africa, to the east of Mozambique and north-west of Madagascar. They are divided between the sovereign state of the Comoros and the French overseas department of Mayotte. The islet of Banc du Geyser and the Glorioso Islands are sometimes included as part of the archipelago.
The Comoro Archipelago enjoys a tropical maritime climate, characterized by slight daytime temperature variations throughout the year of around 26 °C (78.8 °F) at sea-level and by abundant precipitation: 2,679 mm (105.5 in) a year. The average temperature of the sea water is 25 °C (77 °F). There are two seasons in the Comoros: the hot and humid season flowing in from the north-west from November to April and the dry season from May to October. The climate on Mayotte is, nevertheless, noticeably warmer and drier. The climate is also characterized by important local variations in temperature and precipitation according to altitude, relief and the degree of exposure to the elements. Annual precipitation therefore varies in the region of 1,000 to 6,000 mm (39.4 to 236.2 in) and the absolute minimum of 0 °C (32 °F) is reached on the summit of Karthala.
The hot, dry season is caused by a vast low pressure area which extends over a large part of the Indian Ocean and Central Africa. This low pressure favours gusty winds and cyclones. The last cyclone was "Gafilo" which passed close to the Comoros on the 5th of March 2004 causing great material damage. During the hot and humid season it can rain as much as 200 mm (7.9 in) in twenty-four hours. The dry season is calmer. The low pressure moves towards the continent of Asia (this is the Monsoon, the wind blowing from the south-east) and an anticyclone forms below the Comoros. This still does not prevent the islands from having a few gusts of wind, but their intensity is a lot less than during the hot season.