The National Oceanic and Atmospheric Administration (NOAA) reported on August 7, 2023, that July was the hottest month on record for the contiguous United States. The average temperature across the Lower 48 states was 76.9 degrees Fahrenheit, approximately 3 degrees higher than the 20th-century average, surpassing previous records set in July 1936 and July 2012.
Every state in the contiguous U.S. recorded temperatures in the warmest third of their July records, with thirteen states experiencing one of their five warmest Julys on record. Wyoming reported its hottest July and hottest month ever, with an average temperature 5.1 degrees above normal, exceeding its previous record from July 2007.
The record heat was attributed to several heat domes that settled over parts of the country. A significant heat dome affected Washington, D.C., and areas along the East Coast and Midwest during the July Fourth holiday, with temperatures nearing 100 degrees and heat indices rising to 112 in some regions. Another ridge of high pressure brought record temperatures to parts of Montana, Utah, and Wyoming in mid-July.
In contrast, Alaska recorded its coldest July since 2008. Precipitation across the Lower 48 states was below average, with an average of 2.55 inches, which is 0.23 inches below normal, placing July in the driest third of the 132-year record. Looking ahead to August, NOAA predicts above-average temperatures across central and southern America, with parts of California and the southern Plains having a greater than 50% likelihood of experiencing above-average temperatures.