US breaks 132-year high after July becomes hottest month since records beganThis summer has been one for the books with historic heat waves and devastating wildfires across the United States. These systems brought record-breaking temperatures across a vast area stretching from the East Coast through the Plains and into the Southwest. NOAA reported that the average temperature across the Lower 48 states in July reached 3.3 degrees Fahrenheit above the 20th-century baseline. View 4 Images Extreme heat is possible in Southern California (Image: NOAA)‌Human-driven climate change is increasing the intensity, duration, and frequency of heat waves over the long term. During the past month, a severe heat wave swept across the eastern half of the nation through the July 4th holiday weekend, followed by additional waves of extreme heat.