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 winds are predominantly from the southwest in the northern hemisphere and from the northwest in the southern hemisphere. Together with the trade winds, the westerlies enabled a round-trip trade route for early European sailing ships.
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.
