ClimateDashboard-variability-Pacific-North-American-Pattern-graph-20211004-1400px.jpg

Rolling seasonal (3-month) average values for the Pacific-North America Pattern index. During the positive phase, temperatures across the U.S. tend to be sharply split between a warm West and a cool East. In the negative phase, the West is often cooler than average while the East is warmer than average. NOAA Climate.gov image, based on data from the NOAA Physical Science Lab.