A new paper funded by the Modeling, Analysis, Predictions and Projections (MAPP) was published in Nature Climate Change on March 3. 

Statistical studies of rainfed maize yields in the United States and elsewhere have indicated two clear features: a strong negative yield response to extreme heat, and a relatively weak response to seasonal rainfall. 

The authors of the study used the process-based Agricultural Production Systems Simulator (APSIM), a integrative modeling tool for analyzing whole-farm systems, to reproduce these conditions in the Midwestern United States. 

They found a lot of the "drought" impacts on maize in the US are driven by increases in extreme heat rather than decreases in rainfall. 

Read the paper online.