A Flex Alert has been issued by the California Independent System Operator Corporation (ISO) for Tuesday and Wednesday due to high temperatures across the region.

The alert calls for California residents and most of the western U.S to conserve electricity from 5 p.m. to 9 p.m. during these days.

Flex Alerts are issued when the electricity grid is overtaxed due to high temperatures, the ISO said.

To help conserve electricity over the next few days, the ISO asks customers to set thermostats to 78 degrees or higher and to use fans to cool homes.

They also advise homeowners use major appliances in the morning or late evening and turn off lights and appliances that aren’t necessary.

A heat wave moving into the southern California region is sending temperatures soaring. Temperatures on Tuesday and Wednesday could break records for this time of year, according to forecasters.

In San Diego County, inland areas from Escondido to Alpine are expected to see high temperatures in the mid-100s on Tuesday and even coastal cities like Oceanside and San Diego are expected to see highs in the upper-80s.

Much of southern California was under an Extreme Heat Warning and even coastal areas and mountains were under a NWS heat advisory.

Other factors such as limited natural gas supplies, high wildfire risks and fewer electricity imports also contribute to a Flex Alert.

More information about Flex Alerts can be found on the California ISO’s website.