During October, weak La Niña conditions emerged across most of the central and eastern equatorial Pacific Ocean. La Niña is likely to affect temperature and precipitation across the United States during the upcoming months, generally favoring above-average temperatures and below-median precipitation across the southern tier, and below-average temperatures and above-median precipitation across the northern tier. The opposite of an El Niño event, La Niña occurs when sea surface temperatures in the central equatorial Pacific are at least 0.5˚C below average for five consecutive three-month periods. These cooler than normal sea surface temperatures are accompanied by stronger trade winds blowing from east to west, altering weather patterns in the Pacific and around the globe. NOAA’s Climate Prediction Center expects La Niña conditions to continue through early 2018.