Weeks later, the region was still broiling, with the mercury soaring Sunday to a new record of 49C for nearby Los Angeles County.
"It's not so much that climate change is destabilizing historical weather patterns," said Daniel Swain, a climate scientist at the University of California. "In many cases, it's amplifying them."
Hotter temperatures in turn sap the air of humidity and dry out forest and brush on land, creating perfect conditions for wildfires.
In California, "the fires that we're seeing are larger, and faster-moving, and more intense than those you could have expected historically," Swain said.
But attribution science has not explained everything. For example, researchers do not yet fully understand Europe's heatwaves.
"In Western Europe, the increase in heat waves is much stronger than the models predict, and we have no clue why," said Geert Jan van Oldenborgh, an attribution science expert at the Royal Netherlands Meteorological Institute.
Wind, rain, and floods
As average global temperatures have risen by about 1C since pre-industrial times, changes in the atmosphere and oceans are also leading to more intense storms.
Hurricanes overall are getting stronger and spinning slower, as they pick up energy from the heat in the oceans.