Paraty is at its best from April to June and from August to October — the shoulder seasons when the weather is warm but not oppressively hot, the crowds thinner, and the prices lower. The coastal climate means rain is possible year-round, but December through March is the wet season with heavier and more persistent rainfall.
July brings FLIP, the international literary festival, which fills the town to capacity and is worth planning around if literature interests you. The pre-Carnival period (February) also draws large crowds. School holidays in January and July push prices up significantly and accommodation becomes scarce.
Avoid Carnival week if you don't want crowds — or embrace it if you do. Paraty's Carnival is a local affair, less choreographed than Rio's, with the distinctive bloco de lama (mud carnival) where participants cover themselves in black river mud and parade through the streets.