Electricity generation using fossil fuels increased in New England to meet the additional air-conditioning demand during heat waves in June and July. Natural gas-fired electricity generation made up 56% of New England’s generation mix during the week of the June 16 heat wave, peaking at 61% on June 22. Between July 6 and 13, natural gas-fired electricity averaged 58% of the generation mix. Despite the closure of the Mystic Generating Station in Massachusetts, natural gas accounted for more of the generation mix during both periods compared with the five-year (2019–23) average of 48% for the June 16–23 period and 54% for July 6–13.