The United States has recorded its hottest month in more than a century of official temperature records. July’s average temperature was 76.89F (24.94C) across the Lower 48 states, according to the National Oceanic and Atmospheric Administration (NOAA). The Lower 48 refers to all US states except Alaska and Hawaii.The average was 3.3F (1.8C) above the 20th-century average and narrowly surpassed the previous record set in July 1936, when severe drought and extreme heat devastated large parts of the country.The record came after weeks of intense heatwaves, prolonged periods of extreme temperatures and widespread wildfires. Scientists say the severity of the heat is consistent with the effects of human-driven climate change, which is making extreme heat more frequent, longer-lasting and more intense. Heat domes push temperatures to record levelsThree major heat dome events developed across the US during July, trapping hot air over large areas beneath slow-moving high-pressure systems. Extreme heat affected the West, Rockies, Upper Midwest, Gulf Coast and Southeast, with temperatures remaining well above normal for prolonged periods.Every state in the Lower 48 recorded a July average at least 1F (0.6C) above its 20th-century average, NOAA said. Wyoming experienced its hottest July on record, as well as its hottest month ever recorded, with average temperatures 5.1F above normal.The biggest factor behind the national record was unusually warm nights. The average minimum temperature across the Lower 48 exceeded the previous record by 0.7F. Scientists say rising overnight temperatures are particularly dangerous because they prevent the human body from recovering from daytime heat.“If you’re talking heat waves, that nighttime low is incredibly important for determining total heat stress,” said Jeff Masters, a meteorologist with Yale Climate Connections. “So if it doesn’t cool off at night, your body doesn’t have time to readjust to all the heat.”The heat was accompanied by widespread wildfires in the Pacific Northwest and Canada, with smoke affecting large parts of North America. Scientists have linked the growing frequency and intensity of extreme heat and wildfire conditions to the continued burning of coal, oil and gas. Heat takes toll on daily lifeThe extreme conditions also affected Americans’ everyday lives. An AP-NORC poll found that nearly half of respondents said higher electricity bills caused by increased air-conditioning use had a major impact on their finances. Around 40% said extreme heat had disrupted their travel plans, while about two-thirds reported changes to family outdoor activities.Around half said the heat had affected their exercise routines, with the overall impact broader than when similar questions were asked two years earlier.Masters said surpassing a temperature record from the Dust Bowl era was particularly concerning given the historic devastation caused by the drought and heat of the 1930s.
