The scorching summer of 2023 reaches 'mind

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The closest thing to a globe-encircling heat wave continues to bake many Northern Hemisphere locations during mid-July, 2023. Heat near or above all-time highs is surging in locations from Reno, Nevada, to Rome, Italy, and from geographies ranging from desert outposts to the sea surface. Many more records are expected to melt this week, as a consolidating El Niño pattern continues to release greenhouse-gas-trapped heat into the atmosphere that was stored in the ocean during three years of La Niña conditions.

🌡️ Extreme levels of heat are affecting large parts of the Northern Hemisphere ⚠️ Exceptionally high temperatures are breaking records in places and dangerously hot weather will continue in many areas during the next week pic.twitter.com/zebYqdZXGH

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Four stations in Death Valley made a run at beating the all-time world heat record on Sunday, hitting a temperature of at least 53.3 degrees Celsius (127.7°F). This is just short of the all-time world record for reliably measured temperature of 54.4 degrees Celsius (130°F), set on July 9, 2021. (According to an email from Randy Cerveny of Arizona State University, the World Meteorological Organization is working to verify the 2021 reading, and the sensor is currently at an independent testing facility for calibration testing and verification. A reading of 134°F from Death Valley on July 10, 1913, which is currently shown at the AMO/ASU climate site as the world’s all-time record high, has been disputed and discounted as unreliable by multiple researchers.)

Saratoga Spring, located at the south end of Death Valley National Park at an elevation of 198 feet, was the hottest location on Sunday, reporting the sixth-hottest reliably measured temperature in world history: 53.9 degrees Celsius (129°F). Astonishingly, Death Valley’s Badwater Basin, after peaking Sunday at a temperature of 53.6 degrees Celsius (128.5°F), cooled off remarkably slowly overnight, recording a temperature of 48.9 degrees Celsius (120°F) between midnight and 1 a.m. local time, a unique occurrence in world climate history, according to a tweet from climatologist Maximiliano Herrera. In an email, Herrera said he was not aware of any previous cases of a temperature exceeding 46 degrees Celsius (115°F) at midnight local time, commenting, “49°C after midnight is absolutely mind-blowing. It’s more mind-blowing than 40°C in London or 50°C in Canada. It stretches the imagination of what is physically possible on planet Earth.”

🚨 Update on the Tmax recorded yesterday in the Death Valley, #California.🌡️129°F/53.9°C at Saratoga Spring ➡️ only 1°F/0.5°C below the world record!🌡️128.5°F/53.3°C at Badwater🌡️127.7°F/52.8°C at Furnace Creek🌡️127.6°F/52.8°C at Stovepipe Wells#CAwx #heatwave #DeathValley pic.twitter.com/MmNB61p3wg

Here’s is Earth’s new top-ten list of hottest reliably measured temperatures:

1) 54.4° C (130.0°F), 7/09/2021, Furnace Creek (California, U.S.); 2) 54.4° C (129.9°F), 8/16/2020, Furnace Creek (California, U.S.); 3) 54.1° C (129.4°F), 7/10/2021, Furnace Creek (California, U.S.);4) 54.0° C (129.2°F), 6/30/2013, Furnace Creek (California, U.S.);4) 54.0° C (129.2°F), 7/21/2016, Mitribah (Kuwait);6) 53.9° C (129.0°F), 7/16/2023, Saratoga Spring (California, U.S.);6) 53.9° C (129.0°F), 7/17/1998, Furnace Creek (California, U.S.);6) 53.9° C (129.0°F), 7/19/2005, Furnace Creek (California, U.S.);6) 53.9° C (129.0°F), 7/06/2007, Furnace Creek (California, U.S.); and6) 53.9° C (129.0°F), 7/22/2016, Basra International Airport (Iraq).

Kudos go to Maximiliano Herrera (@extremetemps) and Jérôme Reynaud (geoclimat.org) for helping assemble this list.

Portions of 14 states and more than 100 million Americans were under a heat advisory over the weekend, which brought some of the hottest temperatures in history to the U.S. Desert Southwest. Kingman, Arizona, set a new all-time high on Saturday, June 15, with 114 degrees Fahrenheit, and Reno, Nevada tied its all-time high of 108°F on Sunday, June 16.

Several other locations came within 1°F of their hottest temperatures on record on Sunday:

Daggett, Arizona: 117°FFlagstaff, Arizona: 96°FLas Vegas, Nevada: 116°FTonopah, Nevada: 104°FSalt Lake City, Utah: 106°F

The heat may relax slightly across the Southwest later this week, but there is no end in sight for at least the next 10 days for what has become a dangerously prolonged heat wave. Case in point: As of Sunday, Phoenix had recorded 17 consecutive days reaching at least 110°F, and every day through at least Saturday, July 22, is likely to extend that streak. The current record-longest streak of 110°F weather in Phoenix, 18 days (June 12-29, 1974), is thus almost certain to fall by Tuesday, July 18.

Phoenix will break their record for consecutive days at 110+ (tomorrow is day 19) AND this morning broke their record for consecutive overnight lows above 90. They’ve not dropped below 90 for 8 days and counting… #excessiveheat #heat #records @SamWnek @KentonGewecke pic.twitter.com/wFdq6ytMUH

Even more ominously, the low in Phoenix has not dipped below 90°F since July 9. The longest stretch of temperatures remaining at or above 90°F in Phoenix is seven days, which occurred several times, most recently in 2020. That record will be broken if Phoenix remains above 90°F for an eighth day on Monday, July 17. The current forecast does not bring Phoenix below 90°F through at least Saturday, July 22, which would far outpace the old record. Such prolonged streaks of hot nights give people who are sleeping without shelter, or who lack air conditioning, little chance to cool down overnight. In Arizona, 12 heat-associated deaths in Phoenix’s Maricopa County have been identified as of July 11, with 55 more deaths under investigation. Half of the deaths were among homeless people. Maricopa County recorded 425 heat-related deaths last year, up 25% over the prior year.

Conditions also remain scorching in northern Mexico and southwest Texas, where several cities have reached all-time highs in recent weeks. El Paso, Texas, has recorded temperatures above 38 degrees Celsius (100°F) for 32 consecutive days, beating the previous record of 26 days.

In Mexico, 112 people have died from heat-related causes so far in 2023, the health ministry said on June 28. That total was nearly three times higher than the overall number of heat-related deaths in 2022, which peaked at 42, according to Mexico’s health ministry. Nearly all the deaths were attributed to heat stroke, with a handful from dehydration.

In Texas, 13 heat-related deaths were reported as of June 28, with another in Louisiana. Last year, 306 people died of heat-related causes in Texas. Among them were 158 nonresidents, a figure that includes migrants. Since the heat of 2023 is even more intense than in 2022, the heat-related death toll in Texas could again be in the hundreds.

Farther north, several days of beneficial nighttime storms across Oklahoma left much of the state soaked and primed for wilting heat indices that topped 120°F once the heat returned, especially on July 13, as shown below.

Introducing the newest Oklahoma Mesonet extreme: 126F heat index at the Paul’s Valley site. This is our highest ever heat index measurement in our nearly 30 year history. 😳#okmesonet #okwx pic.twitter.com/OPGijwGYNV

Globally analyzed surface air temperatures continue to hover at levels warmer than anything found in analysis extending back to 1979, possibly reflecting conditions that haven’t occurred before in human history. As we discussed in a post earlier this month, the daily global temperature – as projected from station reports and model-based reanalysis – broke 17 degrees Celsius (62.6°F) for the first time in recorded history on July 3, breaking the old daily record of 16.92°C last reached on July 24, 2022.

Astoundingly, every day from that point through July 16 has stayed above that previous record, and there is no immediate end in sight. Oceanic warmth is one of the key drivers of these global air-temperature records, especially with El Niño unlocking vast troves of stored oceanic heat, as noted above.

Across South Florida, the water vapor emitted from the shockingly hot sea surface of recent days – topping 95°F as measured from buoys deployed at at multiple locations near the Florida Keys – has led to brutal heat indices of 105-110°F, and even higher at times. The moisture has also kept nighttime lows excruciatingly high. Key West has stayed at or above 85°F for seven days starting on July 10, crushing the record streak of four days set most recently in 2020. The low of 87°F on July 12 tied the highest minimum ever observed in Key West, and Marathon tied both its all-time daily high (99°F) and all-time daily low (86°F) on July 13. According to Miami-based meteorologist Brian McNoldy, “Miami has never experienced a heatwave like this. Both in terms of longevity and intensity, nothing even comes close.”

At 12pm on Sunday, #Miami hit its record 12th consecutive day with a 106°F+ heat index. The previous longest stretch was 4 days.(It's also the 36th consecutive day with a 100°F+ heat index).https://t.co/0IwczaYZ4Z pic.twitter.com/uwArzMbLqk

Another day… another record… 26 for the month to be exact & 2 more warm low records pending today.With half of the month under our belts, July 2023 is on track to be the warmest on record (& warmest month ever) for #KeyWest & #Marathon.#flwx #FLKeys #FloridaKeys #KeyLargo pic.twitter.com/1O3ZL8r46p

A surge of wildfire smoke from record wildfires burning in Canada pushed through the Midwest over the weekend, arriving along the East Coast on Monday, bringing an air quality index (AQI) in the red “Unhealthy” range to many states. This would have been a remarkable event – if not for the two other such events that have already occurred in the U.S. earlier this summer.

The next chance for a major intrusion of wildfire smoke into the United States from Canada may be this weekend. Starting on Friday, July 21, northerly winds are predicted to pull air from four large out-of-control wildfires near James Bay, Quebec, toward the U.S. This may result in yet another cloud of unhealthy smoke affecting portions of the Northeast U.S. on Saturday and Sunday, according to recent runs of the HYSPLIT model.

A very "summer of 2023" satellite image (8 pm EDT July 15): wildfire smoke pours into the U.S. from Canada, bringing red "Unhealthy" air (left), while another round of thunderstorms with torrential rain moves into the Northeast (right). https://t.co/f8XdI7UssG pic.twitter.com/hBTmcHwTW6

The township of Sanbao in arid north-central China reportedly soared to a high of 52.2 degrees Celsius (126.0°F) on Monday, July 17. If confirmed, this reading will torch the nation’s previous all-time high of 50.5°C (122.9°F), and will also be the hottest temperature ever recorded north of 40 degrees north latitude. Sanbao is in China’s Turpan Depression, the lowest point in the country and roughly analogous to Death Valley in the United States, but considerably further north.

“2023 has been extreme in China with thousands of heat records broken every month but also the national record cold of -53.0C on 22 January,” noted climatologist Maximiliano Herrera on Twitter.

Rome could have its hottest day on record Tuesday, July 18. Temperatures that day are predicted to exceed the all-time highs of 40.8°C (105.4°F) in central Rome and 39°C (102.2°F) at the city’s Fiumicino airport. Italy’s health minister warned people against visiting the Colosseum during the midday heat. Similarly torrid conditions extended eastward across Turkey and Greece, where the famed Acropolis closed to tourists on July 14, and into parts of northernmost Africa.

Many media outlets adopted the name Cerberus – the three-headed “hound of Hades” from Greek mythology – for the Mediterranean heat wave, which prompted Wired to take a thoughtful look into the pros and cons of naming heat waves.

Another day of intense heat in the Mediterranean with 48.1C in Tunisia and few July recordsVery hot night in parts of Greece & Turkey where the Tmins remained above 32C/33CNext days,after trailing other countries without being hit by any record heat,Italy will get its share too pic.twitter.com/s5ZSnDY0Ip

The European heat wave has arrived together with a newly horrific picture of the toll of 2022’s heat across Europe. It typically takes months for researchers to assess “excess deaths”, or the number of people killed by a weather disaster such as a heat wave on top of the numbers who might ordinarily die in a given time period, so comprehensive studies of the 2022 heat impacts are now emerging. A July 10 study by Ballester et al. in Nature Medicine, Heat-related mortality in Europe during the summer of 2022, found that 61,672 heat-related deaths occurred in Europe in 2022, making it the second-deadliest heat wave on record globally: Only the 2003 European heat wave had a higher toll, with 71,130 deaths. The summer of 2022 was the hottest summer on record in Europe; Italy, Spain, Germany, France, the United Kingdom and Greece had the highest number of heat deaths during the summer.

According to EM-DAT, only 10 other heat waves on record have had a death toll in excess of 1,000. Note that heat wave death tolls are notoriously difficult to assess, and it is likely that many historic heat events took large numbers of lives not reflected in these statistics:

1) Europe, 2003: 71,3102) Europe, 2022: 61,6723) Russia, 2010: 55,7364) France/Belgium, 2015: 3,6855) India/Pakistan, 2015: 3,4776) Europe, 2006: 3,4187) India, 1998: 2,5418) U.S. and Canada, 1936: 1,6939) India/Pakistan/Bangladesh, 2003: 1,47210) U.S., 1980: 1,26011) U.S./Canada, 2021: 1,03712) India, 2002: 1,030

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Jeff Masters, Ph.D., worked as a hurricane scientist with the NOAA Hurricane Hunters from 1986-1990. After a near-fatal flight into category 5 Hurricane Hugo, he left the Hurricane Hunters to pursue a... More by Jeff Masters

Bob Henson is a meteorologist and journalist based in Boulder, Colorado. He has written on weather and climate for the National Center for Atmospheric Research, Weather Underground, and many freelance... More by Bob Henson