At the other end of the spectrum, drought and sweltering heat from the Northern Plains to the Pacific Northwest have pushed the Climate Extremes Index even higher. That’s because the index includes temperature extremes as well as their impacts. In this case, the high heat and dry conditions have fueled a brutal wildfire season. More than 400,000 acres are currently burning in Montana alone, which just finished its second driest month on record.
Fires are also raging in Idaho, Oregon, and Washington. Each of those states is battling its own 100,000-acre blaze right now as well. Smoke from those fires has traveled vast distances, bringing hazy skies and poorer air quality to the Plains and parts of the eastern U.S. Rising temperatures have contributed to lengthening wildfire seasons, which are now an average of 105 days longer than in 1970.
• Our Wildfire Tracker shows active wildfires and smoke plumes across the U.S.
• See our special report on climate change, wildfires, and air quality.
Climate change has also tipped the odds toward more extreme heat. Record highs have been outpacing record lows with each passing decade. Since 2015, the number of daily record high temperature in the U.S. has outnumbered the number of daily record lows by more than 3-to-1. One prime example came earlier this month, when San Francisco had its all time record high reaching 106°F on Sept. 1.