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How hot has it been lately?

So hot that San Diego County recorded its highest temperature ever — 124 degrees in Ocotillo Wells.

Airlines canceled more than 40 flights in Arizona.

And a woman suffered third-degree burns on her feet after walking barefoot in Death Valley.

Extreme heat is expected to become a bigger part of life in the West.

Climate researchers at the University of California, Los Angeles, have created forecasts of how many days of extreme heat — defined as more than 95 degrees — the Los Angeles region could expect if nothing was done to reduce greenhouse gas emissions.

Downtown Los Angeles, for example, now has roughly a week’s worth of extreme heat days a year, said Alex Hall, a professor of atmospheric and oceanic sciences at U.C.L.A.