During the last decades, several climate‐modelling studies have forecasted a decrease in precipitation in Southern Amazonia, projecting scenarios of a drier Amazon for the future in relation with deforestation (or forest cover). In this area, only a limited number of analyses using forest cover data and rainfall time series have considered the transitional zones between the Amazon Forest and the Cerrado biome. In this work, we evaluated whether forest cover and rainfall patterns are correlated. The analysis encompassed rainfall times series from 207 rain gauges during the 1971–2010 period, and forest cover data acquired from LANDSAT5 satellite images. The results indicate that, at local level (1–15 km), both seasonal and annual precipitation values are not correlated to forest cover, whereas at the regional scale (30–50 km) contrasting to annual values, significant correlation occurs between forest cover and seasonal precipitation. Additionally, the study suggests that the larger the forest areas, the greater the probabilities of those influencing precipitation at regional scale, in opposite direction to the observed local level effects.