The Climate Prediction Center has announced the formation of a La Ni�a for the second year in a year. La Ni�a is a natural cycle that features cooler-than-average ocean temperatures in the central Pacific Ocean, which has varying effects on weather patterns across the United States and across the world.

Warm water in the western Pacific Ocean shifts eastward toward the west coast of South America, triggering an El Niño, which also features trade winds that are weaker than normal. A similar shift of cold water triggers a La Ni�a, which also features trade winds that are stronger than normal.

The usual La Ni�a winter pattern is for the Mid-Atlantic and Southeast regions to have warmer-than-average temperatures and for New England, the Upper Midwest, and the Northwest to have higher-than-average amounts of cold weather and snow.

The 2017 La Ni�a is forecast to be weak, so a predicted down year for U.S. agricultural production might not be so severe.

The 2016 La Ni�a lasted from July of that year to January 2017.