LAUSR

Understanding what causes weather‐related stresses that lead to crop failures is a critical step toward stabilizing global food production. While there are many sources of weather‐related stresses, the 30–60 days of Madden‐Julian Oscillation (MJO) is the dominant source of subseasonal climate variability in the tropics, making it a potential—but as of yet unexplored—source of crop yield anomalies. Here crop models and observational yield statistics are used to assess whether the MJO affects maize yields. We find that the influence of the MJO is widespread; it can increase or reduce maize yields throughout the tropics. In dry, hot environments the MJO can reduce maize yields by reducing precipitation, decreasing soil moisture, and increasing extreme heat, while in wetter, cooler environments—where water stress is less common—MJO‐forced decreases in rainfall bring increases in solar radiation that benefits maize yields. These results provide a pathway to develop actionable early warnings using subseasonal forecasts.