A record-breaking heat wave across the Western U.S. that’s been checking all the key boxes — intensity, duration, and geographic spread — may just be the opening scene of the worst kind of summer blockbuster, one that’s spreading nationwide.
In the first week of July, at least 10 U.S. towns and cities tied or broke their hottest temperatures recorded on any day in at least 70 years of record-keeping. This rarefied feat is called an all-time record high, as opposed to daily or monthly records, which correspond to the hottest ever observed on a particular date or in a particular month, respectively.
Unusually warm temperatures on both coasts are getting a boost from climate change. Extreme heat expected today across swaths of the West and the mid-Atlantic was made 400% more likely by climate change, according to an analysis by Climate Central, a nonprofit research group.
Heat records falling
The most impressive recent record was the mark set by Las Vegas, Nevada, where the previous all-time high of 117 degrees Fahrenheit was toppled by a full 3°F on Sunday with 120°F. On both July 10 and 11, highs in Vegas are predicted to hit 118°F — which would have been an all-time high had it not been for Sunday. Official weather records for Las Vegas go back to 1937.
And all-time heat is already making its presence felt elsewhere in the nation. Raleigh, North Carolina, hit 106°F on Friday, July 5, breaking the city’s all-time high of 105°F set on multiple occasions. Weather records in Raleigh date back to 1887. The heat index in Raleigh (calculated using heat and atmospheric moisture) hit a modern-day record of 117.8°F.
Adding insult to injury, moisture from the remnants of Hurricane Beryl will be spreading across the northeast U.S., exacerbating heat-humidity combinations that have fueled heat advisories in place Tuesday from Boston to Birmingham.
More heat coming
A shift in the upper-level pattern may allow some monsoon moisture to creep into the Southwest U.S. by late this week, tempering the heat slightly. But seasonal forecasts have been hinting for months that the summer of 2024 will push harder and harder toward the high end of climatology as it progresses, a common U.S. trend during summers when the planet is shifting from El Niño to La Niña. Such forecasts don’t specify city-by-city heat, but they do suggest that much if not most of the contiguous U.S. will be running progressively hotter over time, compared to average readings that are normally torrid enough by the dog days of August.
And it’s not as if the rest of the world has suddenly cooled down after the warmest year in global history, 2023. The Copernicus Climate Change Service reported on Monday that the month of June 2024 was the 13th in a row to set a global monthly record in its database, and the 12th in a row to hit or exceed the crucial benchmark of 1.5°C above preindustrial temperatures.
Globally averaged temperatures will likely dip below record territory later this year as La Niña takes hold. But the heat thus far is already enough to give 2024 a good chance of breaking 2023’s record as the hottest year in global analysis dating back to 1880. We’ll have more in our June 2024 wrap-up post on Friday, July 12.
June 2024 heat records broken
NOAA reported on Tuesday that last month was the second-warmest June in 130 years of record-keeping for the contiguous U.S., coming in behind only June 2021. On the local level, a diverse set of towns and cities from Maine to Nevada recorded their warmest June on record, as compiled in the list of new and broken records below from extreme weather historian Christopher Burt:
- Caribou, Maine: 65.1° (64.9°/2021)
- Flagstaff, Arizona: 66.7° (66.5°/1974)
- Bridgeport, Connecticut: 72.6° (72.2°/2008)
- Hartford, Connecticut: 74.1° (72.6°/1976)
- Reno, Nevada: 75.8° (75.2°/2021)
- Winslow, Arizona: 79.2° (78.1°/2021)
- Baton Rouge, Louisiana: 84.6° (84.5°/2023)
- Corpus Christi, Texas: 87.2° (86.8°/2013)
- Brownsville, Texas: 88.3° (87.3°/1998)
- El Paso, Texas: 89.3° (88.9°/1994)
- Del Rio, Texas: 90.9° (90.5°/2023)
- Las Vegas, Nevada: 94.6° (92.8°/2016)
- Phoenix, Arizona: 97° (95.3°/2021)
Hottest temperatures recorded in Death Valley
The high temperature reached 129.3°F at Death Valley’s Furnace Creek observing station on Sunday, July 7. That was enough to rank as the location’s fourth-hottest reliable reading in more than a century of observation. Death Valley is notorious as the planet’s most consistently scorching location among sites with regular, reliable weather observations. (Note that a much-publicized reading of 134°F at Furnace Creek from July 10, 1913 — still listed by the World Meteorological Organization as the current world heat record — is apparently in error, as exhaustively investigated by Chris Burt. Note also that the frequently photographed digital temperature display at Death Valley National Park’s Furnace Creek Visitor Center is unrelated to the official temperature sensor located on site.)
Here’s Earth’s top-12 list of hottest reliably measured temperatures, in both Celsius and Fahrenheit, including ties. Readings from Furnace Creek in Death Valley (bold face) dominate the list.
1) 54.4° C (130.0°F), July 9, 2021, Furnace Creek (California, U.S.)
2) 54.4° C (129.9°F), August 16, 2020, Furnace Creek (California, U.S.)
3) 54.1° C (129.4°F), July 10, 2021, Furnace Creek (California, U.S.)
4) 54.06° C (129.3°F), July 7, 2024, Furnace Creek (California, U.S.)
5) 54° C (129.2°F), June 30, 2013, Furnace Creek (California, U.S.)
5) 54° C (129.2°F), July 21, 2016, Mitribah (Kuwait)
7) 53.9°C (129.0°F), July 16, 2023, Saratoga Spring (California, U.S.)
7) 53.9° C (129.0°F), July 17, 1998, Furnace Creek (California, U.S.)
7) 53.9° C (129.0°F), July 19, 2005, Furnace Creek (California, U.S.)
10) 53.9° C (129.0°F), July 6, 2007, Furnace Creek (California, U.S.)
10) 53.9° C (129.0°F), July 22, 2016, Basra International Airport (Iraq)
12) 53.8° C (128.8°F), July 22, 2016, Basra-Hussen (Iraq)
It’s possible more entries on this list will get muscled out as the week goes on. As of Tuesday morning, the National Weather Service was predicting Furnace Creek to hit 128°F on Tuesday and Thursday and 127°F on Wednesday and Friday. We’ll add updates here as needed.
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