Rainfall distribution in a región of Amazon rainforest in the north of Mato Grosso

Rainfall predominantly influences economic activity in northern of MatoGrosso. The scarcity of rainfall limits agricultural production, and its excess hinders the flow of production on back roads. These obstacles impose the need for greater knowledge of rainfall in distant regions of the state, such as Paranorte, in Juara-MT. This study aimed to identify the beginning and end of the rainy season, as well as the frequency and duration of dry days, besides to investigate causal relationships of rainfall with ENSO (El Nino de Oscillation Sul) phenomena. Methods based on rainfall quantity and continuity were adopted. The results showed that in Paranorte, the accumulated annual precipitation varies between 2322 and 2720 mm. The months of the year are divided into a dry period (June, July and August), a period of low rainfall (May and September - ≈ 80 mm) and a period of high rainfall (October, November, December, January, February, March and April, with 214 to 464 mm). Prolonged droughts occur most often at the beginning (September) and end (May) of the rainy season. In turn, ENSO phenomena influence rainfall only in spring.