Globally, 2024 was the warmest year on record.
The planet's average temperature was 2.3 degrees Fahrenheit above NASA's 20th-century baseline. According to World Weather Attribution, climate change added an additional 41 days of dangerous heat to the year, and exacerbated 26 of 29 weather events, which killed at least 3,700 people. That included Hurricane Milton in the United States, Typhoon Yagi in Southeast Asia, and deadly flooding in Spain.
Global warming is measured by land surface temperature, whereas air or meteorological temperature determines the daily weather forecast and how it will "feel" outside.
According to the Environmental Protection Agency, surface temperatures are also increasing in the contiguous U.S. Since the late 1990s, these increases have become both more severe and more consistent. The surface temperature has increased every year in the 21st century thus far.
While 2024 was the warmest year on record for the planet, 2025 could surpass it. In June 2025, heat records were broken at 282 locations across the U.S. That included new daily heat records being set in 50 Eastern U.S. cities. And it's not only this country that's burning up—Europe has seen an extreme heat wave that began in June 2025 and continued into July. The New York Times reports multiple deaths and wildfires. While it's too soon to say how many records will be broken when all is said and done, the National Weather Service issued a new warning about a heat dome sending extreme temperatures across the U.S. on July 21, 2025.
The climate situation is constantly in flux, but we can look to past data to see which states tend to be most affected by scorching temps. To find out how and where those heat waves break down, Stacker compiled data from NOAA's National Centers for Environmental Information and determined the warmest states based on their 2023 average temperatures. Each temperature is compared to the 1901-2000 average. Winter refers to December of the preceding year through February of the current year (e.g., in 1919, winter is December 1918 to February 1919), while summer refers to June through August of each year. All temperatures are listed in Fahrenheit, and data was not available for Hawai'i.
Although the warmer climate of southern coastal states is often appealing, these regions also deal with meteorological phenomena—from droughts and floods to tropical storms and hurricanes—that can be devastating. Despite this, in recent years, Florida, Texas, and the Carolinas were the four states with the most significant population increase, which suggests a correlation between year-round warm temperatures; mild, short winters; and living preferences.
Read on to find out the temperatures in the warmest U.S. states, and see what the coldest states in America are here.
