Editor’s Note: This post was originally published on July 6, 2017 and has been updated with the most recent information.
The previous record of 95 degrees was set 131 years ago in 1886. (Fun fact: Downtown LA’s longest-standing heat record is on March 28, when the temperature hit 90 degrees in 1879, according to the National Weather Service).
Southern California is sweating through a heatwave brought on by a high pressure system hovering over the southwest United States. Temperatures picked up Thursday and really started to sizzle on Friday with more than a half-dozen new heat records set from Palm Springs to Woodland Hills.
The Weather Service had forecast high temperatures on Saturday of up to 110 degrees in neighborhoods “away from the coast.” Temperatures closer to the beach were predicted in the 90s.
17th oldest high temperature record in the book for Downtown LA fell today! Record dates back 131 years! https://t.co/CbTPmZe1Ei
— David Biggar (@DavidNBCLA) July 9, 2017
Heat alerts have been issued for the San Fernando Valley, Pomona, and the Santa Clarita Valley, and public health officials are encouraging residents who don’t have air conditioning at home to head over to their nearest cooling center.
Residents seeking relief might want to consider heading to the beach. The Weather Service says, “The coastal plains will see a strong difference between the beaches and a few miles inland, where temperatures could vary by more than 20 degrees.”
Where did this extreme heat come from and when will it end? Here’s what you need to know:
1. When will temperatures peak?
The mercury is forecast to soar to its highest point Saturday.
2. How hot will it get?
Pretty hot. In the Valley, Woodland Hills and Burbank are expected to tie or break their heat records on Friday and Saturday, with temperatures of 112 and 104, respectively. UCLA is forecast to break its record, too, with two days of 94-degree temperatures expected on Friday and Saturday.
The Weather Service accurately predicted that the record for Downtown Los Angeles would fall on Saturday. Its forecast a high of 96 degrees; it turned out to get even hotter than that.
3. What records have already been shattered?
The most wild record was notched Friday in Palm Springs, where the Weather Service recorded a high of 122 degrees. That smashed the record of 117 degrees set more than four decades ago in 1976.
On Friday, the other notable one was at Pierce College in Woodland Hills, where the Weather Service recorded a high of 109 degrees, besting the 2006 high temperature of 108 degrees.
— NWS Los Angeles (@NWSLosAngeles) July 8, 2017
4. Is this normal?
Bill Patzert, a climatologist for the Jet Propulsion Laboratory, tells the Los Angeles Times that Southern California’s warmest months are traditionally August and September, and that the heat waves are “definitely coming earlier this year.”
5. What is to blame for this heatwave?
National Weather Service meteorologist Stuart Seto tells Curbed that the high temperatures are here because of the so-called Four Corners system. Though it’s named for the area where Arizona, Colorado, New Mexico and Utah meet, it stretches all the way into California, he says, bringing potentially record-breaking temperatures along with it.
6. When will it cool off again?
The high pressure system that’s bringing the heat is also picking up monsoonal moisture from Mexico, making for days that are not just hot but also humid. The humidity means that even after the sun goes down, “you’re not getting much relief” from the heat, says Seto. Overnight temperatures are expected to be in the 70s from tonight through Monday, he says.
Even after the temperatures peak, Seto says the cooling will be gradual and temperatures will remain above normal for a few days. Temperatures should be back to normal by Wednesday or Thursday. Until then, maybe hide in the mall and soak up its AC.