An AP data analysis of records from 1999-2019 shows that in weather stations across America, hot records are being set twice as often as cold ones. (Photo: AP)

Over the past 20 years, Americans have been twice as likely to sweat through record-breaking heat rather than shiver through record-setting cold, a new Associated Press data analysis shows.

The AP looked at 424 weather stations throughout the Lower 48 states that had consistent temperature records since 1920 and counted how many times daily hot temperature records were tied or broken and how many daily cold records were set. In a stable climate, the numbers should be roughly equal.

Since 1999, the ratio has been two warm records set or broken for every cold one. In 16 of the last 20 years, there have been more daily high temperature records than low.

The AP shared the data analysis with several climate and data scientists, who all said the conclusion was correct, consistent with scientific peer-reviewed literature and showed a clear sign of human-caused climate change. They pointed out that trends over decades are more robust than over single years.

The analysis stopped with data through 2018. However, the first two months of 2019 are showing twice as many cold records than hot ones. That’s temporary and trends are over years and decades, not months, said National Oceanic and Atmospheric Administration climate monitoring chief Deke Arndt.

“We are in a period of sustained and significant warming and — over the long run — will continue to explore and break the warm end of the spectrum much more than the cold end,” Arndt said.Tap to unmute

Former Weather Channel meteorologist Guy Walton, who has been studying hot and cold extreme records since 2000, said the trend is unmistakable.

“You are getting more extremes,” Walton said. “Your chances for getting more dangerous extremes are going up with time.”

No place has seen the trend more clearly than the Southern California city of Pasadena, where 7,203 days (more than 19 years) went by between cold records being broken. On Feb. 23, Pasadena set a low temperature record, its first since June 5, 1999.

Vermont native Paul Wennberg felt it. He moved to Pasadena in 1998 just before the dearth of cold records.

“Even with the local cold we had this past month, it’s very noticeable,” said Wennberg, a California Institute of Technology atmospheric sciences professor. “It’s just been ever warmer.”

In between the two cold record days, Pasadena set 145 hot records. That includes an all-time high of 113 degrees last year.

“Last year was unbelievable here,” Wennberg said. “The tops of a lot of the hedges, they essentially melted.”