Harmattan is the name of a particular West African trade wind. It blows up from the south near the Sahara Desert into the golf of Guinea. Due to it's passage through the Sahara desert, it is particularly dusty, as it picks up sand as it travels through the desert. It's blowing period is from the end of November until the middle of March. Harmattan is well-known as during it's period of activity for the large amount of dust in the air that severely limits people's ability to see. The amount of dust has also been known to block out the sun for several days. The lack of visibility and dust present due to the trade wind has been dubbed the Harmattan haze.