July Sets Record as Hottest Month in U.S. Since 1895, NOAA Reports

The National Oceanic and Atmospheric Administration announced that July 2024 was the hottest month ever recorded in the United States, based on its temperature series that begins in 1895. The average temperature across the lower 48 states was 3.3°F (1.8°C) above the 20th-century average, edging out the prior records set in July 1936 and July 2012 by about 0.1-0.2°F.

Heat domes persisted over large portions of the country, producing record high maximum and minimum temperatures in more than 600 locations, while fewer than 50 sites recorded cooler-than-average values. No state recorded an average temperature near or below its historical norm for the month.

Thirteen states posted monthly averages that ranked among their five warmest Julys, and Wyoming experienced its highest July temperature and its hottest month on record. Cities such as Denver, Salt Lake City, Miami, Los Angeles and Minneapolis reported July temperatures ranking in the top five warmest for their locations.

Scientists cited both long-term human-induced climate change and a strengthening El Niño event as factors that increase the likelihood and intensity of heat waves. However, studies indicated that individual extreme heat events were more directly linked to climate change combined with natural weather variability than to El Niño alone.

The extreme heat coincided with large wildfires in the Pacific Northwest and Canada, and similar fire activity was reported in parts of Europe, which also experienced its hottest early summer on record. In the United States, the heat contributed to record low water levels in Lake Mead, the nation’s largest reservoir, which supplies water to about 20 million people in the Southwest.

The pattern of elevated temperatures and associated fire risk continued into August, affecting regions from Washington and Oregon to Western Europe.