One of the most brutal heat waves in memory has spread over California. It is poised to set hundreds of records, and it may be more than a week before it relents. Inland areas will be hardest hit — particularly the deserts and valleys.
“It cannot be stressed enough that this is an exceptionally dangerous and lethal situation,” wrote the National Weather Service office in San Francisco. “It may not seem so if you live near the coast, but an event of this scale, magnitude, and longevity will likely rival anything we’ve seen in the last 18 years for inland areas.”
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Temperatures surpassing 100 to 120 will be a daily occurrence over most of the state, while warm nighttime lows offer minimal relief. A powerful and abnormally persistent heat dome will kill off clouds and also keep cooler fog at bay. The heat will also fuel an escalating fire threat; already, the Thompson Fire in Northern California has grown to over 3,000 acres and destroyed structures.
The dangerous heat is projected as far into the future as reliable forecasts are available. All-time records approaching 120 may be threatened as far north as Redding, while Death Valley could approach 130 degrees, which is the highest temperature reliably measured on the planet.
The Weather Service has warned that “numerous heat related fatalities and rolling blackouts” are possible.
The heat wave comes amid the hottest year on record so far for the planet. The last 13 months, including June, have set record highs. According to the science communications firm Climate Central, human-caused climate change has made this week’s heat wave in California at least five times as probable.
The maps that follow help illustrate the seriousness of the heat that lies ahead.
Heat warnings cover 70 percent of the state
More than 70 percent of California is under an excessive-heat warning. Some of the heat alerts issued by the Weather Service extend seven days into the future, which is an unprecedented duration, according to the San Francisco Chronicle.
Cities under excessive-heat warnings include Redding, Sacramento, Fresno, Bakersfield, Santa Barbara, Burbank and Palm Springs.
Heat advisories — for slightly less extreme conditions — are in place for Los Angeles, Santa Maria, San Francisco and other near-coastal cities along with portions of the Sierra Nevada. A few spots right at the coast are not included in any alerts.
Temperatures could climb above 130 degrees
The numbers are startling: Large portions of California will experience highs above 110 degrees over the next week. Some areas will surpass 120. Only areas at the immediate coast and in the higher mountain peaks will escape the triple digits.
Death Valley, which holds the record for the hottest temperature ever measured on the planet, has forecast highs of 126, 128, 130, 131, 131 and 133 over the next six days. Its world-record high temperature of 134 was set in 1913, although there are questions about the reliability of that measurement. In 2020 and 2021, it reached 130 degrees, the highest reliably observed temperature in modern records. Last summer, it hit 129.
Heat dome to near historic intensity
The heat dome responsible for these extreme temperatures is forecast to climb to near record strength and remain parked over California and the southwestern United States for seven to 10 days.
“This is the hottest synoptic pattern that we see,” wrote the Weather Service office in Las Vegas, where all-time highs may be reached.
The heat will not be confined to California but will also affect much of the Southwest and at times swell into the Pacific Northwest as well.
Studies have found that heat domes such as this are becoming larger and more intense because of human-caused climate change.
Calendar-day records will be most common, but some monthly and even all-time marks may be threatened. The number of records set will increase through Thursday and become most numerous between Friday and early next week.
Some of the all-time records in jeopardy include 121 in Palm Springs on Saturday, 118 in Redding on Saturday and 118 in Las Vegas on Monday.
Extreme heat could persist for 7 days
The federal government’s 0 to 4 HeatRisk index is predicted to reach Levels 3 and 4 — considered major and extreme — every day for at least the next week in the Central Valley and deserts.
At these levels, the risk of heat-related illnesses increases substantially, particularly for vulnerable groups such as outdoor workers, the homeless and older adults.
While major coastal cities will be mostly spared, areas just inland will experience multiple days of dangerous heat.
Jason Samenow contributed to this report.
FAQs
It's being produced by a strong ridge of high pressure, also known as a heat dome. High pressure is an area of sinking air. As the air sinks, it compresses and heats things up at the surface. As it camps out over an area for a period of time, it can raise concerns.
What is the record high temperature for Death Valley? ›
Furnace Creek, in Inyo County, California, is home to the headquarters for the national park. The sweltering heat could creep close to the world's record highest temperature of 134 degrees marked at Greenland Ranch in Death Valley on July 10, 1913, according to the National Weather Service office in Las Vegas.
What was the worst heat wave in US history? ›
July 1936, part of the "Dust Bowl", produced one of the hottest summers on record across the country, especially across the Plains, Upper Midwest, and Great Lakes regions. Nationally, about 5,000 people died from the heat.
What is the hottest temperature in California? ›
The current record for the highest reliably measured temperature is 130, set at Death Valley in August 2020 and July 2021, according to Scientific American.
How do you survive a heat wave in California? ›
The Weather Service advised Californians to stay out of the sun, drink plenty of fluids and check on relatives and neighbors during the heat wave. “Take extra precautions when outside. Wear lightweight and loose-fitting clothing. Try to limit strenuous activities to early morning or evening.
What is really causing the heatwave? ›
The mechanism is simple: The burning of fossil fuels adds greenhouse gases to the atmosphere, which traps more heat energy and pushes up average temperatures — which, in turn, also pushes up extreme temperatures.
What is the hottest temperature a human can survive? ›
Externally, the upper limit of the human body's thermoneutral zone—the ambient temperature range in which the body can maintain effectively maintain its temperature and equilibrium—likely falls somewhere between 104 and 122 degrees Fahrenheit, according to a 2021 study published in Physiology Report.
What is the hottest place on Earth ever recorded? ›
According to the World Meteorological Organization (WMO), the highest registered air temperature on Earth was 56.7 °C (134.1 °F) in Furnace Creek Ranch, California, located in Death Valley in the United States, on 10 July 1913.
What is the hottest place in the USA? ›
Death Valley holds the record for the highest air temperature on the planet: On 10 July 1913, temperatures at the aptly named Furnace Creek area in the California desert reached a blistering 56.7°C (134.1°F). Average summer temperatures, meanwhile, often rise above 45°C (113°F).
Will 2024 be hotter than 2023? ›
The current heat “is much more expected than the shattering of records by 0.3 degrees to 0.5 degrees we saw in the latter half of 2023,” Hausfather told CNN. Hausfather estimates a 66% chance that 2024 will be the hottest year on record, and a 99% chance it will be the second hottest.
Without the vegetation and soil moisture, the Plains acted as a furnace. The climate of that region took on desert qualities, accentuating its capacity to produce heat. A strong ridge of high pressure set up over the west coast and funneled the heat northward across the Upper Midwest and Great Lakes.
What was the deadliest heat wave in the world? ›
In 2010, the climate in the northern hemisphere summer was dominated by a series of freak heat waves that proved the most devastating in Russia, where up to 56,000 people died as a result of overheating, droughts, forest fires and smog.
Does California get hotter than Florida? ›
Florida is the hotter and more humid state when compared to California; you might even want to call it tropical. Although Florida doesn't have as much of a diverse landscape as the Golden State, it has miles of incredible beaches, and life is very much focused on the coast.
What's the coldest it's ever been in California? ›
California's lowest recorded temperature was -45 degrees Fahrenheit in Boca on January 20, 1937. The Los Angeles Times reported in 1937 that the low temperatures had brought "influenza, frozen toes, broken water pipes and automobile radiators, icy streets and traffic disruption."
What is the highest temperature ever recorded on Earth? ›
The official highest recorded temperature is now 56.7°C (134°F), which was measured on 10 July 1913 at Greenland Ranch, Death Valley, California, USA.
Why is California having such extreme weather? ›
“We have places where average precipitation has remained more or less the same, but we see more and more extreme events,” AghaKouchak said. In the case of the storm that drenched Los Angeles, climate change likely boosted rainfall, said UCLA climate scientist Daniel Swain during a briefing.
Why is California so hot? ›
However, coastal California is surrounded on the north and east by tall mountain ranges, so the air has to descend down these mountains before reaching the coast. As the air descends in elevation, it gets compressed and warmed; compressing the air adds energy to it, which manifests as heat.
What causes global warming in California? ›
That activity (our use of fossil fuels) has resulted in dramatically increased levels of carbon dioxide and other greenhouse gases in the atmosphere. In California, much of the state's energy still comes from our dependence on fossil fuels like natural gas and oil.
Why is there high pressure over California? ›
California lies within the zone of prevailing westerlies and on the east side of the semi-permanent high pressure area of the northeast Pacific Ocean. The basic flow in the free air above the state, therefore, is from the west or northwest during most of the year.
