There is about a 95% chance of La Niña conditions prevailing through the Northern Hemisphere winter from January to March, a U.S. government weather forecaster said on Thursday.

The La Niña pattern is characterized by unusually cold temperatures in the equatorial Pacific Ocean and is linked with floods and drought.

A transition to more neutral conditions is more likely in the spring of 2021, the National Weather Service’s Climate Prediction Center (CPC) said, pegging the chances of that at about 50%, having said in November that there was a 65% chance of La Niña conditions persisting through spring.

The CPC’s winter projections were unchanged from November.

La Niña persisted through November, and “is anticipated to affect climate across the United States during the upcoming months,” the forecaster said in its latest update.

The weather phenomenon last emerged during the September-November period in 2017 and lasted through early 2018.