The Roaring Forties is a name given, especially by sailors, to the latitudes between 40° and 50°, so called because of the boisterous and prevailing westerly winds. These winds are due to the coriolis effect. Because there is less landmass to slow them down, the winds are especially strong on the Southern Hemisphere, notably in the South Indian Ocean. Wellington, New Zealand, is the world's only capital located in the roaring forties latitudes.

The winds were probably first identified by Dutch sailor Henderik Brouwer in 1610 as a means to rapidly transit across the Indian Ocean en route to Batavia (Dutch East India Company).

See also

• Horse latitudes