The Harmattan is a dry and dusty West African trade wind. It blows south from the Sahara into the Gulf of Guinea between the end of November and the middle of March (winter). The temperatures can be as low as 3 degrees Celsius. The name comes from or is related to an Akan cognate.
On its passage over the desert it picks up fine dust particles (between 0.5 and 10 micrometres).
Read more about Harmattan: Effects