The El Niño Southern Oscillation (ENSO) phenomenon is the strongest driver of inter-annual climate variability around the world and exerts a substantial influence on the climate of cotton production areas in the United States. ENSO phases are characterized by sea surface temperature anomalies in the eastern equatorial Pacific Ocean. When sea surface temperature (SST) is higher than normal the phenomenon is referred as El Niño, and when the sea-surface temperature is lower than normal, the phenomenon is referred to as La Niña. Neutral is the term for when neither El Niño nor La Niña are present in the Pacific. Although El Niño and La Niña return every 2 to 7 years, the tropical Pacific can be thought of as neutral, or near normal, a majority of the time. It is important to recognize that ENSO affects the climate in the northern hemisphere primarily during the fall, winter, and early spring months of the year but still may impact summer crops in certain regions of the United States. The main goal of this report is to evaluate the influence of ENSO on cotton yield variability.