Rainy season in Caño Negro - Costa Rica is from the beginning of May to the end of November approximately. The season begins with very light rain, occasionally. It is difficult to find an all-day rainy situation. Probably, the rainiest period is around October and November. But even so, it probably won’t rain all day. In any case, as our tours are private, we would organize with you the best moment of the day to go discover the refuge.