Highways Baking at 158F Signal Red-Hot Summer From US to China (1)

In northern China, road surfaces have soared to 158F (70C). In California’s Central Valley, temperatures are reaching into the triple digits Fahrenheit. Across much of Spain, the mercury has risen so high that it’s prompting warnings for tourists.

Weeks before the official start of the Northern Hemisphere’s summer, signs are emerging that the coming months will be blistering in North America, Europe and Asia. There’s even a chance that the season could shatter global high-temperature records, said Daniel Swain, a climatologist at the University of California, Los Angeles.

Farmers harvest wheat in Suixi county, Anhui province, China, on May 28.

Photographer: Wan SC/Feature China/Future Publishing/Getty Images

The scorching conditions threaten to tax power grids, wilt crops and ...