Doldrums

Doldrums, region of calms, light variable winds, and thunderstorms, girdling the oceans near the equator and varying in position and extent according to the season. The doldrums lie between the belt of northeasterly trade winds of the northern hemisphere and the southwesterly trade winds of the southern hemisphere, roughly between latitude 10 ° south and 10 ° north. Air heated at the surface of the earth rises in the doldrum region and flows northeastward and southeastward, at heights from about 0.8 km (about 0.5 mi) to 6 km (4 mi) to form the “antitrade winds.” The doldrums are low-pressure calm latitudes and the horse latitudes are high-pressure calm latitudes (see Wind).