The summer of 2025 has seen record-high temperatures with a dangerous heat wave raising temperatures on the East Coast above 100°F. Prolonged extreme heat harms human health and undermines energy infrastructure. People keep air conditioners on high to stay cool, which strains electric utilities already under stress from overheated transmission lines. During the June 2025 heatwave, demand on the New England electrical grid approached max capacity. The increase in energy usage caused energy sector CO2 emissions to skyrocket, further contributing to the greenhouse effect, warming the atmosphere. This heat wave is not an isolated incident. There were 60% more heat-related power outages between 2014-2023 than in the decade prior. The damage caused by heat waves like this illuminates the weakness of the US's electrical infrastructure.
Climate Central's "Climate Shift Index" (CSI) measures how climate change has increased the likelihood of a particular daily temperature. Climate Central conducted an analysis using this tool and determined that climate change made the June 2025 heat wave at least five times more likely to occur for 69 million Americans, and at least three times more likely to occur for half of Americans. High daily temperatures on the East Coast at the end of June were more than 20°F warmer than average.
Electricity providers in the US are struggling to keep up with demand during heat waves and avoid blackouts. PJM Interconnection, the largest US electrical grid manager that covers approximately 20% of Americans, struggled to keep electricity flowing during the June heat wave. The North American Electric Reliability Corporation's (NERC) annual assessment said the US has "insufficient power reserves to operate in above-normal conditions". Blackout events in the United States increased by over 60% in the most recent five-year reporting period.
When heat waves and grid failure occur in tandem, 68-100% of the exposed urban population experiences an increased risk of heat stroke or exhaustion. Cities around the country have implemented heat plans to address rising temperatures. Washington, D.C.'s plan offers guidance to community members, including those experiencing homelessness, on how to stay cool during heat waves. DC is one of 81 US cities with cooling centers. One step cities could take to lower temperatures is to replace concrete areas with green space and tree cover. Studies have shown that trees have a cooling effect on their surroundings. Contrarily, concrete has been shown to raise cities' temperatures by up to an extra 22°F.