Record-shattering temperatures brought on by searing desert winds wilted Southern California for a fourth straight day Friday.

The mercury in downtown Los Angeles hit 100 degrees at 1 p.m. Friday, eclipsing the record for the day of 88 set in 1962, the National Weather Service said.It was 106 at the Los Angeles Civic Center Thursday afternoon, making it the hottest April day on record after topping Wednesday's record high of 105 and Tuesday's 100. The previous record of 100 for an April day was set on April 23, 1910.

But the humidity remained a barely discernible 9 percent through much of Friday, lessening the discomfort.

Long Beach had a temperature of 92, San Diego reported 93 and it reached 96 in Santa Ana.

A fire Thursday night on the roof of the UCLA Medical Center knocked out the hospital's air-conditioning system, forcing officials to close the emergency room and cancel all elective surgery Friday.

"It's uncomfortable, especially if you're sick," UCLA spokesman Rich Elbaum said. "The nurses are doing an incredible job by keeping patients comfortable. They've been giving them tepid baths and patting them down in bed."

Portable fans were set up throughout the massive building and selected lights were turned off to help keep temperatures down, Elbaum said. Repairs on the building's cooling tower were expected to be completed by Friday afternoon.