Topline
Extreme heat in Europe has been blamed for hundreds of deaths, a national monument has been shuttered in Greece and millions of Americans are under heat warnings from the National Weather Service as a scorching July gets underway around the world.
A woman holds a fan during a heat wave in New York City, on June 22, 2025.
Key Facts
Parts of 18 states across the country are under heat advisories Tuesday, including extreme heat warnings in California, Arizona and Nevada, where temperatures could hit 120 degrees.
A heat advisory along the East Coast has been issued in 11 states, including Virginia, North Carolina, Massachusetts, New Jersey and New York, and a heat index of up to 100 degrees is expected in New York City.
Red flag warnings, which warn of dry, hot and windy weather perfect for wildfire combustion, accompany heat warnings in parts of Washington, Oregon, Idaho and Nevada.
The NWS’s Climate Prediction Center has said above-normal temperatures are expected across the entire contiguous United States for July, August and September.
Parts of Europe are experiencing yet another heat wave this week that has forced the temporary closure of the Acropolis in Athens, Greece, where temperatures were predicted to hit 107 degrees Tuesday, and led to a health alert issued for some areas of England as the U.K. prepares for temperatures topping 90 degrees.
In South Korea, an early end to monsoon season led to heat wave warnings issued across most of the country this week.
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What To Watch For
The World Meteorological Association has said global mean near-surface temperatures are expected to remain at, or near, record levels for the next five years. A May report says there is an 80% chance at least one year between 2025 and 2029 will be warmer than 2024, currently the hottest year on record, and that Arctic warming over the next five winters is predicted to be more than three-and-a-half-times the global average.
Tangent
Parts of Europe were debilitated by a heat wave last week that has been blamed for hundreds of deaths and shuttered popular tourist attractions. A powerful heat dome combined with a marine heat wave in the Mediterranean Sea, causing temperatures up to 9 degrees above average to soar across the continent. Temperatures broke records in Spain (which reached 114.8 degrees) and Portugal, which recorded its hottest temperature ever (115.8 degrees). Portugal’s directorate-general for health said the country recorded 284 excess deaths during the heat wave, a majority of which were people older than 85. Italy and France each reported two deaths and hundreds of hospitalizations in the heat wave, and four people died in Spain. In France, the Eiffel Tower summit was closed to tourists for several days and the Beznau Nuclear Power Plant in Switzerland was forced to close one of its reactors due to high river-water temperatures. Wildfires blazed and forced evacuations on the Greek island of Crete, in Portugal and Spain and in five districts in Turkey, where 50,000 residents were temporarily displaced and dozens of people were injured.
Key Background
Since the industrial revolution introduced skyrocketing use of fossil fuels and other climate-harming behaviors in the mid-1800s, Earth has been warming at an unprecedented rate. Widespread and rapid changes in the atmosphere, ocean and biosphere have occurred since, and NASA says the current warming rate hasn’t been seen in the last 10,000 years. In 2023, a sweeping climate report declared Europe the world’s fastest-warming continent, with a temperature 2.3 degrees Celsius hotter than it was in pre-industrial times. Globally, 2024 was the hottest year on record. Temperatures in 2024 were 2.3 degrees Fahrenheit above NASA’s 20th-century baseline and the breaking of the record came after 15 consecutive months of monthly temperature records (from June 2023 through August 2024). The hottest day ever recorded was on July 22, 2024, when global surface air temperatures reached an average of 62.87 degrees Fahrenheit.
