I have to make a correction, for the first premise is simply wrong. Voyages from Europe to the Americas did not last months, let alone the better part of a year. A voyage from one side of the Atlantic to the other would commonly last some 15-20 days, depending on the atmospheric factors. What you probably have in mind is Columbus' first voyage, that departed from Palos on August 3rd of 1492 and arrived to Guanahani on October 12th 1492. This two dates, however, don't give us a real picture.

Columbus did depart from Palos on August 3rd, and arrived to Guanahani on October 12th, but he had stayed for one month in the Canary Islands, allegedly repairing the ships, the sails, getting water and other importante supplies. Since he left the Canary Islands until he arrived in Guanahani, the navigation was 33 days (as Columbus himself explains in his letter to Santángel, or as pointed out by Oviedo and Las Casas), but he took what is possibly the most inadequate route, navigating on a same parallel, which in this case resulted in traversing the sargasso sea, and before that traversing a part of the Atlantic where the winds basically stop. Had Columbus known the current of the Canary Islands, his voyage would have taken some twenty days, arriving easily to the Windward Isles. This point is clear from Columbus second voyage, which left the Canary Islands on October 13th 1493, and arrived in Martinique on November 3rd. On his third voyage, he left the Canary Islands on June 21st 1498, and arrived in the island of Trinidad on July 3rd.