Ozone levels in Tucson and other Arizona urban areas are increasing as temperatures hit record or near-record levels every year with growing scientific consensus that continued increasing temperatures will make future ozone levels, and, in effect, health risks worse.
July was record warm for Alaska's northernmost city and the hottest month on record for the globe at Death Valley.
The Southwest's monsoons are becoming more intense, even as less rain falls on average.
A scorcher of a heat wave broke temperature records across the West and helped fuel new wildfires.
Planes have been grounded in Phoenix as life-threatening heat descends across the Southwest.
Rising temperatures are causing less of each winter’s snowpack to flow down a major river as water.
After years of widespread, intense drought, the U.S. is experiencing its smallest drought footprint since 2000.
The massive rains and flooding in Louisiana are the latest in a string of extreme U.S. storms this year.