Source: The Library Of Congress Country Studies
The climate of Seychelles is tropical, having little seasonal variation. Temperatures on Mahé rarely rise above 29 C. or drop below 24 C. Humidity is high, but its enervating effect is usually ameliorated by prevailing winds. The southeast monsoon from late May to September brings cooler weather, and the northwest monsoon from March to May, warmer weather. High winds are rare inasmuch as most islands lie outside the Indian Ocean cyclone belt; Mahé suffered the only such storm in its recorded history in 1862. Mean annual rainfall in Mahé averages 2,880 millimeters at sea level and as high as 3,550 millimeters on the mountain slopes. Precipitation is somewhat less on the other islands, averaging as low as 500 millimeters per year on the southernmost coral islands. Because catchment provides most sources of water in Seychelles, yearly variations in rainfall or even brief periods of drought can produce water shortages. Small dams have been built on Mahé since 1969 in an effort to guarantee a reliable water supply, but drought can still be a problem on Mahé and particularly on La Digue.
Data as of 1994