Most major cities are now experiencing two more extreme heat streaks each year compared to 1970, according to an analysis by Climate Central, which found that human-caused climate change is driving the trend.
The nonpartisan research group defines an “extreme heat streak” as at least three days in a row where a city’s daily high temperature is hotter than 90% of all highs during the last few decades.
That’s happening even more frequently than the national average in several parts of the Mountain West. Denver and Colorado Springs have experienced four more extreme heat streaks than they did 50 years ago. Phoenix and Tucson, Ariz., Cheyenne, Wyo., Helena, Mont., and Las Cruces, N.M., have three more streaks…