Phoenix set to break record for 110-degree days as extreme heat plagues West Coast

Extreme late-season heat is plaguing the West Coast from Los Angeles to Seattle with heat alerts issued for more than 65 million Americans across six states.

Phoenix has surpassed 110 degrees 55 times this summer, tying the record set just last year. Phoenix is expected to break that all-time record Thursday as temperatures are forecast to reach near 114 degrees.

Over the last 30 years, Phoenix has seen an average of just 21 days a year over 110 degrees.

There have been 177 heat-related deaths in Maricopa County, which includes Phoenix and its suburbs, from January through August, according to the Maricopa County Department of Health. The deaths of 436 other people are being investigated as to whether they are heat-related.

Last year, 645 heat-related deaths were recorded in the county, according to the Maricopa County Department of Public Health. 

Phoenix reached 111 degrees on Wednesday, extending its record for the most consecutive days at 100 degrees or higher to an even 100. The previous record was 76 days at 100 or above.

Elsewhere in the West, record temperatures of 106 degrees are possible in Medford, Oregon; 102 is possible in Portland, Oregon; and 91 degrees is possible in Seattle. 

In addition to record heat, a red flag warning has been issued for Washington state, where very low humidity and hot temperatures could help spread wildfires. 

Numerous wildfires have been burning in Oregon and some evacuations have been issued.

The hot weather will continue for the West through this weekend.

Long Beach, California, could get close to a record 100 degrees on Saturday and Boise, Idaho, could approach a record 95 degrees on Sunday.

ABC News' Ginger Zee contributed to this report.