Against Expectations, Southwestern Summers Are Getting Even Drier

The Southwest, already the driest region in the United States, has become even drier since the mid-20th century, particularly on the hottest days, according to new research. Humidity has declined in summers over the past seven decades, the research showed, and the declines have accelerated since 2000, a period of persistent drought in the region. Extreme heat coupled with lower humidity increases wildfire risk, said Karen McKinnon, a climate scientist at the University of California, Los Angeles, and lead author of a paper in Nature Climate Change describing the research and findings.