La Niña—the cool phase of the El Niño-Southern Oscillation climate pattern—emerged in the tropical Pacific in August 2020. Forecasters estimate a 75% chance these conditions will last through Northern Hemisphere winter. La Niña winters tend to favor warm and dry conditions in the southern tier of the U.S.

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(image at left) Cooler-than-average surface waters in the central and eastern Pacific in August 2020 are one sign of La Niña.