The arc of Paraguay River headwaters area is subjected to great pressure of human activities on the environment, especially due to agriculture. Thus, studies that aim to analyze the weather patterns in this region are essential, for their importance as subsidy to agricultural models that visualize the best relation between production and energy consumption. The objective of this work was to analyze the yearly, seasonal and monthly rainfall distribution, as well as to provide different levels of precipitation probability, using the Gamma function. The average rainfall at the region was 1,513.97 mm, being that 50.26% of this occurred on the summer and only 2.69% on the winter. The months with highest rainfall average were from November to March, and the lowest from the months of June and August, characterizing the whole region. The expected rainfall at 75% of probability during the rainy season, ranges from 229.98 mm in January at the municipal district of Tangará da Serra, to 83.85 mm in November at Barra do Bugres.
Rainfall; temporal distribution; levels of probability
