Not a perfect relationship, but there are generalizations that can be pulled from this chart.  This graphic shows the Southern Oscillation Index (bars) and the year-over-year change (%) in sugarcane yields (solid line, with 1.0 being same).  When the SOI is in negative phase, this is an El Nino indicator, which tends to correlate with a warmer and somewhat wetter pattern in Brazil’s Centre-South, where most of the sugarcane is grown.  So in years where the SOI is negative, the y/y %change in yields tends to show a positive response.  Rather than generating a rule (ie., negative SOI=positive yield response), what is more interesting is that in years where the SOI was strongly negative (typically strong El Nino years), the magnitude of the y/y change in yields tends to be more pronounced, giving yields a healthy boost over the prior year.  As we are potentially fading out of La Nina over the coming months, this will be a factor that we are monitoring closely.