• Parana River;
  • near-decadal climate variability;
  • solar motion

[1] A link between climate and the motion of the Sun around the barycenter of the solar system has been suggested, mostly on the basis of interannual cycles observed in climatological data from the Northern Hemisphere. This study provides empirical evidence for a connection between this solar motion and discharge of the Paraná River, which has the second largest drainage basin of South America. Solar motion is described here by the absolute value of the time derivative of solar angular momentum (∣τ∣). For the time period 1904–2008, the time evolution of both ∣τ∣ and river discharge is dominated by cycles with periods between 7 and 9 yr. Within this frequency band, a statistically significant anticorrelation is found between ∣τ∣ and river discharge with minima of ∣τ∣ coinciding with increased river discharge.