New Mexico, Utah and Colorado each recorded their warmest summer on record in 2026, and Arizona tied its record, according to NOAA's National Centers for Environmental Information. The contiguous United States averaged 74.4 degrees Fahrenheit from June through August, 3.0 degrees above the 20th-century average and the warmest summer in the 132-year record, beating the previous records set in 1936 and 2021 by 0.4 degrees.

The heat was global. NCEI's monthly global climate report found the planet's surface temperature ran 2.38°F (1.32°C) above the 20th-century average, the warmest August in its 1850 to 2026 record. Global sea surface temperature also reached an all-time high as El Niño conditions persisted.

For Southwest households, the most telling detail is what happened after dark. Average nighttime low temperatures in August were record warm in Arizona, Utah, New Mexico, Colorado, California, and Nevada, which means less overnight relief for people without reliable cooling.

A Summer with Little Overnight Relief

August alone broke national records. The Lower 48 averaged 75.6°F, and daytime highs averaged 88.6°F, both the warmest on record. California, Nevada, New Mexico and Colorado each set records for their warmest August average temperature, while California and New Mexico also posted their warmest average daytime highs.

These are statewide averages rather than city readings, but they reflect the conditions residents of the region lived through, with record-breaking warmth widespread across the West, Southwest, southern Rockies and southwestern Plains.

The World Meteorological Organization reported that data from Europe's Copernicus Climate Change Service showed August tied July 2023 as the warmest month ever recorded in its dataset, at 1.65°C above the estimated pre-industrial baseline. WMO and NCEI both said the Northern Hemisphere had its warmest summer.

El Niño and the Race for the Warmest Year

WMO said El Niño is now firmly established and will intensify into a very strong event, with big impacts on rainfall and temperature patterns well into 2027. That added ocean heat sits on top of a long-term warming trend.

Forecasts for the full year differ. NCEI's Global Annual Temperature Outlook says 2026 will very likely rank among the five warmest years, with the highest probabilities favoring second place. Berkeley Earth climate scientist Zeke Hausfather told the Associated Press that "it is increasingly likely that 2026 ends up beating 2024 as the warmest year on record," and that 2027 is almost certain to beat both. These are estimates, not certainties, and final rankings will not be known until early next year.

A record summer is consistent with long-term warming, but NOAA's report is not a formal attribution study. It does not calculate how much of this summer's heat came from climate change versus El Niño or natural weather patterns.

Drought and Fire Risk Follow the Heat

The heat arrived alongside expanding drought. As of Sept. 1, about 59.1% of the Lower 48 was in drought, an increase of about 10.5 percentage points since early August. NCEI said drought persisted across much of the interior West, although it contracted in portions of the Southwest, Southeast and Mid-Atlantic.

California received just 0.20 inches of rain all summer, its fifth-driest summer on record and driest since 2002. Nature World News has reported on federal projections that Lake Mead could hit a record low as drought strains the Colorado River system.

The fall outlook is mixed. NCEI said drought improvement or removal is expected in areas from the Southwest to the central Rockies. Its September wildfire outlook, however, flags above-average significant fire potential for parts of the Northwest and northern Great Basin, portions of the Upper Midwest, much of the southern Plains and Lower Mississippi Valley, and parts of southern Florida and Puerto Rico, rather than the core of the Southwest.

Staying Safe as Warmth Lingers into Fall

Relief may be slow. NOAA says September temperatures are favored to run above average across much of the country, from the Southwest and Rockies to the Great Lakes, Gulf Coast and Southeast.

The people at greatest risk from heat include older adults, young children, outdoor workers, people with chronic illness and households without air conditioning. Practical steps include checking the National Weather Service forecast before outdoor work or exercise, knowing where local cooling centers are, and checking on neighbors who live alone. Households struggling with summer electric bills can ask their utility about payment plans or energy assistance programs.

Water use deserves attention too. Drought restrictions vary by city and utility, and residents should follow local rules rather than assume normal watering schedules apply.

NOAA's next El Niño update is scheduled for Oct. 8. The Southwest just lived through a record-setting summer, and the global heat behind it has not yet peaked.

What Readers Want to Know

Which states set summer heat records? New Mexico, Utah and Colorado set records for their warmest summer, and Arizona tied its record, according to NOAA.

Was August 2026 the hottest ever globally? NOAA ranked it the warmest August since 1850, and Copernicus data show it tied July 2023 as the warmest month in that dataset.

Will 2026 be the hottest year on record? It is uncertain. NOAA's outlook favors second-warmest, while Berkeley Earth's Zeke Hausfather says a record is increasingly likely.

Why do warm nights matter? Record-warm nights mean less cooling after sunset, which adds strain for people without reliable air conditioning.

Is drought getting worse? Nationally, drought expanded to about 59.1% of the Lower 48 by Sept. 1, though it contracted in parts of the Southwest.