These steady winds are found in both hemispheres on the eastern and equator sides of the subtropical high-pressure belts. They vary in position and strength year on year but rarely fail. Moderate steady wind and sunshine have made sailing in the trades almost legendary. With a full moon and spinnaker set; few places can offer better sailing. Towards the western and equator sides of the trade wind belt, moisture increases in the air, giving rise to more squally weather. Details of the extent and strength of trade winds can be found on routing charts.

Sometimes found in the trade winds, easterly waves are shallow troughs moving westwards between 10 and 20 knots. There is fair weather ahead of the trough and cloudy and squally weather behind. The wind follows the arrows shown in the diagram.

This is the thermal equator of the world - moving north and south following the sun but lagging by a couple of months. The mean position, however, is north of the equator. Overland, the movement is much greater than over the sea, bringing rainy seasons to tropical lands. It is a band where the northeast and southeast trade winds meet - hence the name Intertropical Convergence Zone (ITCZ). As with all surface convergence, this gives a general rise of air, lower surface pressure, and rain, usually in huge squalls. Therefore, the weather in the ITCZ is usually calm, interrupted by vicious squalls and towering black clouds. The gusts can reach gale force with stinging rain.