Lauren Rosenthal left, and her sister Sara Rosenthal on paddle boards off East End Beach in Portland on Tuesday. The two were visiting Maine from Philadelphia and Richmond, Virginia, where the recent heat has been more intense. Gregory Rec/Staff Photographer

Portland’s record-breaking heat wave came to an end early Sunday morning when temperatures dipped below 60 degrees for the first time in more than a month.

The 32-day streak was the longest in Portland’s history, besting a 24-day run in 1988, said Jon Palmer, a meteorologist with the National Weather Service office in Gray.

While consistently warm low temperatures have made it difficult for residents to cool off, the city managed to avoid extreme highs during July, according to Palmer.

“It really hasn’t been an overly hot month,” he said. “Believe it or not, the Portland Jetport still hasn’t even gotten above 90.”

Portland’s average temperature this July sat at just under 72 degrees through Saturday, 1 1/2 degrees higher than its historical average. But this difference was entirely due to warmer-than-usual low temperatures; high temperatures were slightly cooler than average.

Heavy rainfall throughout the month probably contributed to the warmer nights, Palmer said. When skies are cloudy, the difference between high and low temps tends to be smaller.


The temperature at the Portland Jetport finally dropped to 57 degrees at around 5 a.m. Sunday morning, according to National Weather Service data. And while the heat quickly climbed back up as the sun rose, the next week could bring more positive news for those hoping for cooler mornings and evenings.

“We’re looking at a little bit more of a drier pattern this week,” Palmer said. “It does seem like the pattern is slowly but surely changing.”


It’s difficult to definitively tie Portland’s most recent hot streak to climate change, Palmer said. But the city has seen more heat waves in recent years, including a 21-day run in 2020 and a 15-day spell in 2019, which could suggest an emerging pattern.

“We can’t really say for sure, but there does seem to be a trend recently of having longer strings like this,” Palmer said. “From what we’ve been seeing, it looks like phenomena like this could become more frequent in the upcoming decades.”

Recent heat waves across Europe, Asia, and the American Southwest were all made worse by global climate change, according to a recent report from World Weather Attribution.


The study linked the heatwaves to the continuing buildup of warming gases in the air. A stagnant atmosphere, warmed by carbon dioxide and other gases, made the European heat wave 4.5 degrees hotter, the one in the United States and Mexico 3.6 degrees warmer, and the one in China 1.8 degrees warmer, the study found.

“Had there been no climate change, such an event would rarely have occurred,” Mariam Zachariah, a climate scientist at Imperial College of London and the lead author of the study, told the Associated Press. She called heat waves in Europe and North America “virtually impossible” without the increase in heat-trapping gases since the mid-1800s. Statistically, the one in China could have happened without global warming.

A changing climate could continue to transform Maine and its waterfronts in the coming years, according to the University of Maine’s 2020 update to its Maine’s Climate Future report. One projection suggests Maine’s air temperature average air temperature could climb by six degrees while sea levels rise by up to three feet by 2050.

Dan Krell sits on a bench in the shade at the top of the Eastern Prom in Portland on Tuesday, July 25. Krell said that heat doesnÕt typically bother him. Temperatures are forecast to get hotter by the end of the week and Maine has also set a record for having the most consecutive nights where the low temperature has not dropped below 60s. Gregory Rec/Staff Photographer

Meanwhile, rising sea levels and extreme heat in other parts of the country could displace families and trigger high levels of migration to inland Maine, Boston University researcher Nathan Phillips suggested at a conference in Skowhegan last month.

While slightly cooler than last year, Portland’s average temperature this July would be the seventh-highest on record, according to data from the National Weather Service. Three of the city’s five hottest Julys since 1940 have come in the last five years.

As climate change fans hotter and longer heat waves, breaking record temperatures across the U.S. and leaving dozens dead, the poorest Americans suffer the hottest days with the fewest defenses. Air conditioning, once a luxury, is now a matter of survival.

While billions in federal funding have been allocated to subsidize utility costs and the installation of cooling systems, experts say they often only support a fraction of the most vulnerable families and some still require prohibitive upfront costs. Installing a centralized heat pump system for heating and cooling can easily reach $25,000.

President Biden announced steps on Thursday to defend against extreme heat, highlighting the expansion of the Low Income Home Energy Assistance Program, which funnels money through states to help poorer households pay utility bills.

This report contains material from the Associated Press.

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