California residents have been asked to conserve electricity for another day as a heat wave sweeps the West.
The state's energy grid operator issued another statewide Flex Alert, calling for conservation from 4 to 9 p.m. PT due to "increasing high heat, tightening energy supplies and more potential strain on the grid."
Californians are strongly urged to lower electricity use, setting thermostats to 78 degrees or higher, health permitting.
In addition, the California Independent System Operator (ISO) instructed residents to avoid using major appliances and turn off unnecessary lights.
Before the Flex Alerts, people can pre-cool their homes and use major appliances.
"Tomorrow’s Flex Alert is the fourth consecutive call for conservation, as much of the state remains gripped in an extensive heat wave. With increased heat in the forecast for California and the West, the power grid operator is again expecting high electricity demand throughout Labor Day weekend and into next week, primarily from air conditioning use," the ISO explained.
Citing preliminary data, the operator said consumer and business conservation had been helpful in keeping the grid stable last week.
As summer comes to a close, heat lingers and the National Weather Service said widespread daily highs were forecast to reach the super 90s and triple digits in the interior sections of California.
The agency said dozens of daily high temperature records could be set in the region over the holiday weekend.
The call turn off lights and appliances comes just days after the state moved to ban gas-powered cars by 2035.
California Gov. Gavin Newsom signed an executive order last Wednesday that will allow his state to ramp up its electricity supply.