An Extreme Heat Warning remained in effect across much of Los Angeles County through 8 p.m. Thursday, September 10. The National Weather Service warned that temperatures in affected areas could range from 92 to 108 degrees. Humidity was also making conditions feel more uncomfortable. The heat comes during a year that has already brought record temperatures and damaging heat waves to Europe and other parts of the world.
In inland Orange County, an Extreme Heat Warning covered Anaheim, Santa Ana, Fullerton, Garden Grove, Orange, Irvine and Mission Viejo. High temperatures of 90 to 100 degrees were expected Thursday. Forecasters also warned that overnight temperatures in the 70s would provide limited relief.
The worst of the heat arrived Wednesday, September 9. Parts of Los Angeles County were expected to reach as high as 108 degrees. Downtown Los Angeles had a forecast high near 101 degrees with heat index values possibly reaching 112.
The heat was made worse by lingering tropical moisture connected to former Hurricane Marie. The added humidity helped create what forecasters described as oppressive conditions. CBS Los Angeles reported that daytime temperatures were running about 10 to 15 degrees above normal in many areas.
Conditions are expected to improve as the week ends. Humidity should drop Friday and temperatures are expected to move closer to normal by Saturday. Still, officials warned that the current heat presents a serious health risk.
The National Weather Service advised residents to drink plenty of fluids and spend time in air-conditioned places when possible. People were also urged to check on relatives and neighbors. Children and pets should never be left inside parked vehicles.
The Southern California heat is part of a much larger period of unusual warmth around the world.
Copernicus Climate Change Service reported Thursday that August 2026 was the warmest August ever measured in its dataset. The global average surface temperature was 16.96 degrees Celsius, or about 62.5 degrees Fahrenheit. That was 0.85 degrees Celsius above the 1991-2020 August average.
August was also tied with July 2023 as the warmest month ever recorded globally. The temperature was 1.65 degrees Celsius above the estimated average for the period from 1850 to 1900. It was the first month since November 2025 to rise more than 1.5 degrees above that preindustrial level.
A single month above 1.5 degrees does not mean the long-term Paris climate target has officially been crossed. That target is based on temperatures averaged over a much longer period. However, the latest figures show how high global temperatures have climbed.
Europe has faced some of the most severe heat this year.
Spain recorded 61 days of heat wave conditions across the mainland and Balearic Islands in 2026. That was the highest total on record and far above the previous record of 41 days in 2022, according to Spain's AEMET weather agency.
Spain also had its hottest summer since national records began in 1961. Its average summer temperature reached 24.5 degrees Celsius, or 76.1 degrees Fahrenheit. That was 2.4 degrees Celsius above the 1991-2020 average.
Other parts of Europe also struggled with repeated heat waves during the summer. Italy placed its major cities under its highest heat health alert in August. Temperatures reached 42.8 degrees Celsius, or about 109 degrees Fahrenheit, in Bagnacavallo in northern Italy.
The heat caused problems far beyond personal discomfort. Low river levels disrupted shipping and electricity production. Hungary was forced to sharply reduce output at its nuclear power plant because of low Danube River levels. Romania also took emergency measures to maintain cooling water for a nuclear reactor.
France also saw nuclear plants reduce electricity production because river water had become too warm for normal cooling operations. A later European heat wave pushed power prices sharply higher as people increased their use of air conditioners while electricity supplies became tighter.
Agriculture has also suffered. France expects its 2026 wine production to be among the lowest in three decades after heat waves and drought damaged vineyards. Production is forecast at about 33.9 million hectoliters. That would be 17% below the average for the previous five years.
Western Europe as a whole recorded its hottest summer on record, according to Copernicus. Europe overall had its third-warmest summer.
Extreme heat is also contributing to serious problems in Southeast Asia.
Indonesia is dealing with its most severe wildfire season in more than a decade. High temperatures and drought linked to strong El Niño conditions have helped fires spread across Sumatra and Borneo. More than 113,000 cases of respiratory illness connected to smoke had been reported by September 9, according to Indonesia's Health Ministry.
More than 12.5 million people in seven Indonesian provinces have been exposed to smoke and haze. The pollution has also spread into neighboring countries including Malaysia and Singapore.
Scientists say climate change is increasing the background temperatures in which these weather events occur. Copernicus said the record global heat in August reflected both high land temperatures and record or near-record ocean temperatures. Strong El Niño conditions in the Pacific are adding another source of warmth this year.
The World Meteorological Organization has also warned that heat waves and wildfires can worsen air pollution. Hot conditions can increase ground-level ozone while wildfires produce dangerous fine particles that can travel far from the flames.
For Southern California, cooler weather should begin arriving after Thursday. But the current event fits a broader pattern seen around the world this summer. Record temperatures are affecting health, agriculture, power supplies and water resources in many countries.
As Southern California residents wait for relief, the latest global climate data show that extreme heat remains one of the most widespread weather threats of 2026.