Today's Edition
The New York Times News Service
Temperatures hovered above 100 degrees Fahrenheit (37.7 Celsius) along parts of the California coast early Friday, creating unbearable conditions past midnight as officials warned that the excessive heat would last through the weekend.
The nighttime heat ranged from the upper 80s to the 100s across the coasts of Santa Barbara, Ventura and Los Angeles counties, according to the National Weather Service.
Such high temperatures happen at that time of night there about once a year, Bryan Lewis, a meteorologist at the National Weather Service office in Oxnard, California, said in a phone interview.
"We’re not seeing a ton of release at night,” he said, adding that temperatures remained high elsewhere in the region early Friday, hovering in the high 70s and lower 80s in more populated areas. "That’s absolutely concerning.”
Excessive heat warnings and heat advisories were in effect across the broader Western United States early Friday. More than 31 million people were under excessive heat warnings in parts of Arizona, California, Nevada and Oregon.
An excessive heat warning is the most serious heat alert, issued when the hot weather can cause illness or death if people fail to take precautions, according to the National Weather Service. The warnings in the Los Angeles area were expected to last into Monday.
Warm nights can be deadly. Deaths can climb 10% to 50% on days when the nights are hot, studies have shown, because it becomes harder for people to cool down after a hot day. Outdoor workers, older people, young children, the sick and people who are homeless are especially vulnerable.
In most of the United States, nights have warmed faster than days because of climate change, giving fewer people relief from the day’s heat. As a result, air conditioners and other appliances have also had less downtime at night, increasing emissions and the risk of breakdowns.
The nighttime heat in California followed a day of record highs during a weekslong heat wave. Burbank Airport reached 114 degrees Thursday, which tied with the record reached once in July 2018 and twice in September 2020, the National Weather Service said.
Phoenix marked its 100th consecutive day of temperatures of at least 100 degrees Wednesday, and the city hit 116 degrees Thursday - the latest point in September that has ever occurred. In Los Angeles, temperatures could reach 117 degrees Friday.
Lewis said the persistence of heat at night near Santa Barbara, California, was caused by the lack of a sea breeze - winds from the west that normally bring cooler ocean air inland, acting as a natural air conditioner. Because of a high-pressure system over the land, dry, hot gusts from inland have instead blown toward the sea.
That weather phenomenon has been called "sundowner” winds in the Santa Barbara County area, named after the time of day when they occur.
Lewis urged people to drink more water than they think they should and to keep an ice pack on their neck to prevent overheating.
"Right now, it’s nighttime,” he said, "so we can’t really say, ‘Stay out of the sun.’”
