westerlies

The prevailing winds found at mid-latitudes, between 30° and 60°N and S of the Equator. In the N hemisphere the prevailing direction is from the SW; in the S hemisphere it is from the NW. Westerlies in the S hemisphere are stronger because there is a smaller land mass, and are known as the Roaring Forties, from the latitudes at which they occur.

The westerlies are the prevailing winds in the middle latitudes between 30 and 60 degrees latitude, blowing from the high pressure area in the horse latitudes towards the poles.

The westerlies can be particularly strong winds, especially in the southern hemisphere, where there is less land in the middle latitudes to cause friction and slow the winds down. The strongest westerly winds in the middle latitudes can come in the Roaring Forties, between 40 and 50 degrees latitude.