Maricopa County has confirmed eight heat-associated deaths this year as of July 1, and another 40 cases are under investigation. 

More than a third of those were people over the age of 75. 

Tom Frieders is a warning coordination meteorologist with the National Weather Service. He says Phoenix is in the middle of a historic heat wave. 

"We've actually been above 110 for 10 days in a row. So that actually comparing to the longest stretch ever of 110 plus days that we're now in seventh place," Frieders said. 

There is a 50% chance that Phoenix could tie the record with 18 days above 110 degrees in a row.