The temperature in Palm Springs matched the all-time record while highs for this date were set in two other spots in Riverside County Thursday.
The high in Palm Springs was 123, according to the National Weather Service. The temperature in Palm Springs was also 123 on Aug. 1, 1993, July 28, 1995 and July 29, 1995.
Records for June 17 were also set in Idyllwild and Thermal.
The high in Idyllwild was 96, breaking the previous record of 92 set in 1961. Daily records were also set in the mountain community Tuesday and Wednesday. The weather service has kept records in Idyllwild consistently since 1943.
The 118-degree high in Thermal broke the record for June 17 set in 2008. The weather service has kept records in Thermal consistently since 1950.
A Flex Alert calling on residents to voluntarily cut their power use will be in effect from 6 to 9 p.m. Friday, the California Independent System Operator, which manages the state’s power grid, announced.
According to Cal-ISO, residents are urged to take steps prior to the alert taking effect, such as pre-cooling their homes, using major appliances and closing window coverings to preserve cool air indoors. Once the alert takes effect, residents should set their thermostats to 78 degrees or higher, avoid using major appliances and turn off all unnecessary lights.
Excessive heat warnings that began Monday will continue through 9 p.m. Saturday in the Riverside County Mountains, the Inland Empire and the San Gorgonio Pass near Banning, and through 9 p.m. Sunday in the Coachella Valley.
The cause of the dangerous heat is a ridge of high pressure that strengthened and expanded over the Southwest this week, ushering in the sweltering conditions that are expected keep Riverside County in the triple digits during the daytime hours for the entire week.
The system will begin weakening on Sunday, when temperatures are expected to begin subsiding, the weather service said.
The weather service said the extreme heat will significantly increase the potential for heat-related illnesses, particularly for those working or participating in outdoor activities.
People should be prepared to drink plenty of fluids, stay in an air-conditioned room, stay out of the sun and check up on relatives and neighbors.
While young children and pets should never be left unattended in vehicles under any circumstances, the weather service said that’s especially true during warm or hot weather — when car interiors can reach lethal temperatures in a matter of minutes.
The county recently opened cooling centers in multiple locations, where residents who don’t have access to air-conditioning can stay during the heat of the day. A complete list of options is available at www.capriverside.org/cool-centers.