LAS VEGAS >>  A heat wave smothering the West was rewriting record books, likely tying a more than century-old U.S. record in California as Las Vegas and other cities came out of their hottest June ever into a July that brought little relief.

California’s Death Valley National Park tentatively recorded a high temperature of 129 degrees, which would tie the all-time June record high for the United States, the National Weather Service said Monday. It could take months to verify whether Sunday’s high beats the record set in 1902 at Volcano, a former town near the Salton Sea in southeastern California.

The reading, however, was definitely short of the all-time world record of 134 degrees set in Death Valley on July 10, 1913.

Las Vegas temperatures have been at 115 and above in recent days — including a record-tying 117 on Sunday — helping make the hottest June ever in Sin City.

Weather service meteorologist Chris Stachelski said Las Vegas will continue to bake in near-record temperatures at least through Thursday.

Temperatures reached a record 120 degrees in parts of the Lake Mead National Recreation Area east of Las Vegas, National Park Service spokeswoman Christie Vanover said Monday.

A man died of unknown causes at the lake Sunday, while five people were treated during the weekend for heat-related illness and more than a dozen others were rescued in separate incidents, park service officials said.

Metropolitan Phoenix saw just a slight drop in temperatures after experiencing record-breaking weekend heat. Saturday’s 119-degree high marked the fourth-hottest day in metro Phoenix since authorities started keeping records more than 110 years ago. Sunday’s high was an only slightly less sweltering 115 degrees.

Tragedy struck north of Phoenix as hot gusty winds fueled an out of control wildfire that overtook and killed 19 firefighters near the town of Yarnell. Forestry spokesman Art Morrison said the firefighters were forced to deploy their fire shelters, tent-like structures meant to shield firefighters from flames and heat.

In Utah, the third-hottest June in Salt Lake City history gave way to still more heat, with temperatures of 100 degrees or higher expected through Thursday.

That would mark eight straight days of triple-digit heat, said weather service meteorologist Nanette Hosenfeld. The record is 10 consecutive days, set in 2003.

Temperature records were shattered across Southern California and the region was expected to broil under a massive heat wave through Wednesday, though more record highs were unlikely.

Paso Robles on California’s Central Coast matched a 63-year-old record with a temperature of 107 degrees. The same temperature set a record for the city of Campo in San Diego County.

Sunday’s high of 115 in Lancaster in north Los Angeles County represented not just a record for June 30 but an all-time high — surpassing the 114 degrees recorded 53 years earlier.

Monday’s high temperature of 89 in Seattle broke the old July 1 record of 87 at Seattle-Tacoma International Airport, recorded in 1995 and 1968. The high Sunday at Sea-Tac was 93, but that didn’t break a record.

In Oregon, circling buzzards led neighbors to discover sheep with full-grown wool that had dropped dead of the heat in a field in rural Marion County.

The sheriff’s office said Monday that 30 to 40 had died in the 80-acre field covered with green standing grass.

Sheriff’s spokesman Don Thomson told the Statesman Journal deputies responded Sunday and gave remaining sheep water and food. More than 200 survived.