Contiguous U.S. breaks its record for hottest month ever, NOAA says

July was “a wild weather month,” setting a record as the warmest month ever for the contiguous United States, the National Oceanic and Atmospheric Administration said Monday.

Temperatures last month averaged 76.9 degrees Fahrenheit as above-average warmth blanketed the U.S., and several locations in Idaho, Utah, Wyoming and Montana saw all-time high temperature records since NOAA started keeping track in 1895.

Last month was 0.1 to 0.2 degrees warmer than July 1936 and July 2012, according to the agency. July also broke the record for the average low temperature, at 64.2 degrees, surpassing July 2022 by 0.7 degrees.

A heat wave that began in early July placed more than 185 million people under heat alerts, including residents of multiple major metropolitan areas, like Boston, New York City, Philadelphia and Washington, D.C. The Independence Day parade in the nation’s capital was among several events that had to be canceled or postponed due to the extreme heat.

Just a week after heat and severe storms marred July Fourth celebrations, a heat dome trapped more of the country under relentless warmth and humidity. Salt Lake City reached an all-time high on July 12, with temperatures reaching 109 degrees, according to the National Weather Service.

Forecasters had called the unusually prolonged bout of heat “exceptionally rare” for some locations, even in mid-July.

The extreme temperatures also brought heavy rain and major floods — including in the Texas Hill Country and eastern New York — despite below-average precipitation across the contiguous U.S., NOAA said. The U.S. precipitation average for July ranked third driest on record. 

As of Aug. 4, about 48.5% of the contiguous U.S. was in drought, according to the Drought Monitor. In Puerto Rico, more than two-thirds of the island was in drought, and San Juan residents and neighboring communities have started rationing water.

Dry and warm weather that persisted over much of the interior West, Southwest and Rockies also fueled wildfires, including in eastern Oregon, where wildfires burned over 140,000 acres in July, according to NOAA.

Globally, last month was the joint second-warmest July on record, according to the World Meteorological Organization.

The WMO also warned that above-normal temperatures are expected over the next three months, as the weather phenomenon known as El Niño is likely to push global temperatures to record highs.

“El Niño is one of the most closely monitored climate phenomena in the world. But forecasts in themselves do not prevent hazards, people do,” WMO Secretary-General Celeste Saulo said in an update last month. “This El Niño developing against the backdrop of unprecedented ocean heat and rising temperatures, provides governments and communities with a window of opportunity to anticipate risks and act before impacts unfold.”