El Niño Southern Oscillation (ENSO) is a global phenomenon that drives local and regional climate variability. It also affects various sectors in daily life, including agriculture. Influence of El Niño is well documented in literatures and generally it gives detrimental effects on agriculture. But, our understanding on local impact to main crops in Langkat Regency, North Sumatra is limited. This study explored the influence of the 2015/16 El Niño in Langkat Regency particularly on local climate variability, and production of on rice, corn, and soybean. We used daily climate data for 1981-2016 combined with agricultural production for 2010-2016. The onset of rainy season was determined using climate data, and we divided the analysis based on the seasonal zone (ZOM). Then we statistically compared agricultural production of each main crops (rice, corn, soybean) annually to the annual mean production for 2010-2016. The results showed that El Niño shorten a wet season in 2015/16 for all ZOMs, with a decreased rainfall between 7% to 30% compared to the normal year. In contrast, agricultural production had risen for 6%-16% due to human interventions during El Niño period. The interventions were comprised of two activities: the use of climate information for agricultural management and expansion of planting area. The findings suggested that climate information will be benefit to society when it is properly used.