Rio Carnival is a wild 4 day celebration, 40 days before Easter. It officially starts on Saturday and finishes on Fat Tuesday with the beginning of Lent on Ash Wednesday after which one is supposed to abstain from all bodily pleasures. Carnival with all its excesses, celebrated as a profane event, can be considered an act of farewell to thepleasures of the flesh. It usually happens in February, the hottest month in the SouthernHemisphere, when the Rio summer is at its peak.
source:yousaytoo