July has seen multiple days with temperatures over 100 degrees.

The heat set off two warnings last week from operators about peak energy use, and now concerns are growing that the heat could get worse.

“Over the past 40 years or so, across the United States, generally we're seeing an increase in the number of days with extreme heat,” climate scientist Kristina Dahl said.

Dahl, with the Union of Concerned Scientists, has researched climate change for 25 years and is now studying heat waves.

“With that average warming that we're also experiencing as a planet, we're also seeing frequency and intensity of heat waves in places like Texas and around the world increasing,” Dahl said. “So the sorts of conditions Texans are experiencing this week and this summer can be expected to grow more frequent and more intense in the coming decades."

Data points to a trend that this hot July won't be the worst.

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