Will it be a Good Ski Season? Correlation between El Nino and Snowfall


This study investigates the correlation between El Niño and weather across the US. El Niño is defined as warmer waters in the equatorial Pacific and La Niña is colder waters in that same area. Correlations were computed between the El Niño index and the average winter precipitation, snowfall, and temperature of 25 US cities. It was found that El Niño has different effects on on winter weather by geography: the southern US is colder and wetter during an El Niño, while the north is warmer and drier. The effects of La Niña are opposite. There is about a five month time lag between the El Niño index and wintertime snowfall, meaning that the El Niño of the previous August is the best predictor of winter weather for most US cities. Although El Niño is a good predictor of winter weather, the prediction is just as large as the variability.