La Niña and El Niño Patterns
Typical January-March weather conditions and atmospheric circulation (jet streams shown by red and blue arrows) during La Niña and El Niño conditions. Cloud symbols show areas that are wetter than normal. During La Niña, winters tend to be unusually cold in Alaska and western Canada, and dry throughout the southern United States. El Niño leads to unusually warm winter conditions in the northern U.S. and wetter than average conditions across the southern U.S. (Figure source: NOAA).