Here Are the Stunning Heat Records Set So Far This Summer

Breaking high-temperature records is a hallmark of climate change. With more and more heat being trapped in the atmosphere by the greenhouse gases emitted when humans burn fossil fuels, heat records are now set increasingly more often than cold ones.

Climate change leads to longer, stronger and more frequent heat waves. A recent study from the World Weather Attribution group found that some of this summer’s record-setting heat waves would have been “virtually impossible” without climate change. A hot summer of the past is an average one today, and the current hot summers will be considered pretty average in the future.

Extreme heat kills people. In the U.S., it claims more lives than hurricanes, tornadoes and floods—combined. It is particularly dangerous for young children, the elderly, those with health conditions such as asthma and heart disease, those who work outside and the unhoused.

Below is a running list of some of the records that have been set this year.

Local-Level Records

Under the influence of a tenacious heat dome, Phoenix blew past its record for the longest stretch of days with high temperatures at or above 110 degrees Fahrenheit (43.3 degrees Celsius), which lasted for 31 days. (The previous record, set in 1974, was 18 days.)

Phoenix also tied the record (previously set in 2021) for the most days in a row—six—with a high of at least 115 degrees F (46.1 degrees C). And it did that twice: there was one day in between each stretch with a high of 114 degrees F (45.6 degrees C). Additionally, the city has broken the record for the most days at or above 115 degrees F within a single year, with 19 days so far in 2023 (the previous record was 14 days).

And Phoenix hasn’t only sweltered during the day. Nighttime lows hit an all-time high record of 97 degrees F (36.1 degrees C), breaking an earlier peak on July 19. The city has seen a record 16 consecutive days with a low of 90 degrees F (32.2 degrees C) or higher. The previous record of seven days was set twice in 2020.

The soaring highs and still roasting overnight temperatures combined so that, in July, Phoenix had the hottest month of any U.S. city on record, with an average temperature of 102.7 degrees F (39.3 degrees C).

July was also the hottest month on record for Miami, Fla. The city recorded a heat index (a measure that factors in humidity to determine what the temperature feels like to the human body) above 100 degrees F (37.8 degrees C) for 46 days, according to local meteorologist Brian McNoldy. This is by far the most days in a row to reach that level. (The previous record, set in 2020, was 32 days.) Additionally, Miami saw a record 13 consecutive days with a heat index of 106 degrees F (41.1 degrees C) or higher and a record two days in a row where the heat index topped 110 degrees F. It also had three pairs of days with a heat index of 109 degrees F (42.8 degrees C) or higher. Before this year, there were no consecutive days where the heat index reached that level.

San Angelo, Tex., set an all-time high of 114 degrees F (45.6 degrees C) in June as a heat dome stayed parked over the area for weeks. It was one of many heat records that have broken around the state this summer.

Algiers, the capital of Algeria, set an all-time record high of 119.7 degrees F (48.7 degrees C) on July 23 amid a brutal heat wave affecting areas all around the Mediterranean.

Palermo, the capital of the Italian region of Sicily, hit an all-time record high of 116.6 degrees F (47 degrees C) on July 24, breaking its previous record by more than 3.6 degrees F (two degrees C). Temperature data there extend back to 1791.

Regional and National-Level Records

Sanbao township in China’s Xinjiang Uygur region set the country’s all-time record high temperature of 126 degrees F (52.2 degrees C). And Spain’s Catalonia region had its hottest-ever temperature of 113.7 degrees F (45.4 degrees C).

On July 8 a town in Canada’s  Northwest Territories recorded a temperature of 100 degrees F . The location was the farthest north of the 65-degree latitude line where that has ever happened in the Western Hemisphere.

Chile, Argentina and surrounding areas in southern South America have been experiencing summer heat in the middle of the Southern Hemisphere winter. Two spots in central Chile reached 101.7 degrees F (38.7 degrees C) on August 1, a national record high for the month and more than 40 degrees F (22 degrees C) above normal, the Washington Post reported.

This July was the hottest on record in Japan, and Tokyo saw a record 13 days with highs at or above 95 degrees F (35 degrees C). The previous record was seven days, based on data going back to the late 19th century.

Global Records

On the global scale, the planet saw its hottest June on record this year by a wide margin. And July is expected to be not only the hottest July on record but also the hottest month ever recorded on Earth. The first week of July was also provisionally the hottest week on record for the whole planet.