 Annual temperature variations are small, although diurnal variations can be extreme.The harmattan, a hot, dry, and often dust-laden wind, blows from the Sahara throughout the long dry season and is the prevailing wind, except along the narrow coastal strip, which is influenced by oceanic trade winds.Most rain falls during the short rainy season (hivernage), from July to September, and average annual precipitation varies from in the far south to less than in the northern two-thirds of the country.