The heat wave baking the county for six days began to ease Tuesday, but scattered power outages continued as temperatures in the high 90s persisted in some areas.

About 3,500 Southern California Edison customers in the Camarillo area endured a brief heat-related power outage Tuesday afternoon, said Rudy Gonzales, a regional manager for the utility. Nearly 34,000 customers were affected by outages Tuesday throughout Edison's territory.

Hundreds of other homeowners in Ventura County lost power over the holiday weekend, and Simi Valley Hospital experienced brownouts as near-record heat drove energy consumption to an all-time high.

Southern California Edison customers on Friday used 23,303 megawatts, more than any other day in the company's 110-year history, Gonzales said.

The total demand for energy then decreased slightly as businesses closed during the weekend. But demand increased in residential areas and led to hundreds of small blackouts as people cranked up air conditioners, Gonzales said.

In Ventura County, Simi Valley endured the hottest weather. It was 111 degrees in the city Sunday and Monday.

Elsewhere in Southern California, scorching temperatures were blamed Tuesday for at least 13 deaths. Twelve of the deaths occurred in Los Angeles County, said Capt. Ed Winter of the coroner's office, and a 13th death was confirmed in San Bernardino County.

In Ventura County, Simi Valley saw the most power outages. Beginning about 2 p.m. Saturday, Simi Valley Hospital was beset by a series of brownouts, said hospital spokesman Jeremy Brewer. Within 30 minutes of the first brownout, the hospital had its backup generator operating, Brewer said.

Medical equipment operated normally, but the hospital's air conditioning faltered,, he said. Nearly 70 fans were distributed to patients while hospital staff members handed out ice and wet cloths to keep people cool.

Traci Reilly, a Simi Valley resident whose father was in the hospital recovering from a stroke last week, called the situation "unacceptable."

Reilly's father "was pretty much incapacitated because of the heat," she said. "I just think it's crazy that they can operate a hospital without a properly working air-conditioning unit."

The hospital Tuesday afternoon was still using its backup generator to deal with unexpected dips in power, but patient areas were cooled to 71 to 74 degrees, Brewer said.

"We apologize for any inconvenience this had on our patients," Brewer said.

About 350 Edison customers in Simi Valley lost power for about 24 hours starting at 8 p.m. Sunday when a bank of transformers overloaded and failed, Gonzales said. The outage affected an area near Kuehner Drive and Katherine Road.

Patches of electricity outages were reported to City Hall when it reopened on Tuesday.

"There were few large-scale outages," said Mike Sedell, city manager.

One resident said his electricity had been out since Saturday.

Rick Pugh said his Simi Valley home lost power Saturday night and functioned on a trickle of energy until Tuesday afternoon. Without air conditioning, the home was more than 90 degrees in the afternoon, and his four children had trouble sleeping, he said.

"It's been a really long weekend," he said.

Cafe Fiore in Ventura had to close all day Sunday because of a power outage, said owner Maria Fiore. "I know I lost like $10,000," Fiore said, adding that she would seek to recoup the loss through insurance.

In all, Edison has had to replace about 750 of its 700,000 transformers during the past week, Gonzales said.

About 500,000 customers have been affected by outages, about a third of the number affected during a heat wave in July 2006, he said.

The current heat wave peaked over the weekend, with temperatures topping 100 in Simi, Ojai, Fillmore and Thousand Oaks, according to the National Weather Service. Simi Valley and Ojai temperatures dropped into the high 90s on Tuesday.

The decline is the beginning of a cooling trend expected to last seven to 10 days, said Edan Lindaman, a meteorologist with the weather service's Oxnard office. Forecasts show temperatures continuing to decline as sea breezes, low clouds and fog return to the county, Lindaman said.

— Staff writer Anna Bakalis contributed to this report.