There are ocean currents........like the Gulf stream, flowing from south to north in the Atlantic........and trade winds............

Though Columbus was wrong about the number of degrees of longitude that separated Europe from the Far East and about the distance that each degree represented, he did possess valuable knowledge about the trade winds, which would prove to be the key to his successful navigation of the Atlantic Ocean. During his first voyage in 1492, the brisk trade winds from the east, commonly called "easterlies", propelled Columbus' fleet for five weeks, from the Canary Islands to The Bahamas. The precise first land sighting and landing point was San Salvador Island.^[32] To return to Spain against this prevailing wind would have required several months of an arduous sailing technique, called beating, during which food and drinkable water would probably have been exhausted.

Instead, Columbus returned home by following the curving trade winds northeastward to the middle latitudes of the North Atlantic, where he was able to catch the "westerlies" that blow eastward to the coast of Western Europe. There, in turn, the winds curve southward towards the Iberian Peninsula.^[33][34]